diff --git a/src/wp-includes/class-wp-image-editor-gd.php b/src/wp-includes/class-wp-image-editor-gd.php
index fdd5586866..303f5004c0 100644
--- a/src/wp-includes/class-wp-image-editor-gd.php
+++ b/src/wp-includes/class-wp-image-editor-gd.php
@@ -140,12 +140,16 @@ class WP_Image_Editor_GD extends WP_Image_Editor {
 	 * Resizes current image.
 	 * Wraps _resize, since _resize returns a GD Resource.
 	 *
+	 * At minimum, either a height or width must be provided.
+	 * If one of the two is set to null, the resize will
+	 * maintain aspect ratio according to the provided dimension.
+	 *
 	 * @since 3.5.0
 	 * @access public
 	 *
-	 * @param int $max_w
-	 * @param int $max_h
-	 * @param boolean $crop
+	 * @param  int|null $max_w Image width.
+	 * @param  int|null $max_h Image height.
+	 * @param  boolean  $crop
 	 * @return boolean|WP_Error
 	 */
 	public function resize( $max_w, $max_h, $crop = false ) {
@@ -192,24 +196,37 @@ class WP_Image_Editor_GD extends WP_Image_Editor {
 	 * @param array $sizes {
 	 *     An array of image size arrays. Default sizes are 'small', 'medium', 'large'.
 	 *
+	 *     Either a height or width must be provided.
+	 *     If one of the two is set to null, the resize will
+	 *     maintain aspect ratio according to the provided dimension.
+	 *
 	 *     @type array $size {
-	 *         @type int  $width  Image width.
-	 *         @type int  $height Image height.
-	 *         @type bool $crop   Optional. Whether to crop the image. Default false.
+	 *         @type int  ['width']  Optional. Image width.
+	 *         @type int  ['height'] Optional. Image height.
+	 *         @type bool ['crop']   Optional. Whether to crop the image. Default false.
 	 *     }
 	 * }
-	 * @return array An array of resized images metadata by size.
+	 * @return array An array of resized images' metadata by size.
 	 */
 	public function multi_resize( $sizes ) {
 		$metadata = array();
 		$orig_size = $this->size;
 
 		foreach ( $sizes as $size => $size_data ) {
-			if ( ! ( isset( $size_data['width'] ) && isset( $size_data['height'] ) ) )
+			if ( ! isset( $size_data['width'] ) && ! isset( $size_data['height'] ) ) {
 				continue;
+			}
 
-			if ( ! isset( $size_data['crop'] ) )
+			if ( ! isset( $size_data['width'] ) ) {
+				$size_data['width'] = null;
+			}
+			if ( ! isset( $size_data['height'] ) ) {
+				$size_data['height'] = null;
+			}
+
+			if ( ! isset( $size_data['crop'] ) ) {
 				$size_data['crop'] = false;
+			}
 
 			$image = $this->_resize( $size_data['width'], $size_data['height'], $size_data['crop'] );
 
diff --git a/src/wp-includes/class-wp-image-editor-imagick.php b/src/wp-includes/class-wp-image-editor-imagick.php
index f3c9451ec3..4ebed4bae7 100644
--- a/src/wp-includes/class-wp-image-editor-imagick.php
+++ b/src/wp-includes/class-wp-image-editor-imagick.php
@@ -211,12 +211,16 @@ class WP_Image_Editor_Imagick extends WP_Image_Editor {
 	/**
 	 * Resizes current image.
 	 *
+	 * At minimum, either a height or width must be provided.
+	 * If one of the two is set to null, the resize will
+	 * maintain aspect ratio according to the provided dimension.
+	 *
 	 * @since 3.5.0
 	 * @access public
 	 *
-	 * @param int $max_w
-	 * @param int $max_h
-	 * @param boolean $crop
+	 * @param  int|null $max_w Image width.
+	 * @param  int|null $max_h Image height.
+	 * @param  boolean  $crop
 	 * @return boolean|WP_Error
 	 */
 	public function resize( $max_w, $max_h, $crop = false ) {
@@ -255,13 +259,17 @@ class WP_Image_Editor_Imagick extends WP_Image_Editor {
 	 * @param array $sizes {
 	 *     An array of image size arrays. Default sizes are 'small', 'medium', 'large'.
 	 *
+	 *     Either a height or width must be provided.
+	 *     If one of the two is set to null, the resize will
+	 *     maintain aspect ratio according to the provided dimension.
+	 *
 	 *     @type array $size {
-	 *         @type int  $width  Image width.
-	 *         @type int  $height Image height.
+	 *         @type int  ['width']  Optional. Image width.
+	 *         @type int  ['height'] Optional. Image height.
 	 *         @type bool $crop   Optional. Whether to crop the image. Default false.
 	 *     }
 	 * }
-	 * @return array An array of resized images metadata by size.
+	 * @return array An array of resized images' metadata by size.
 	 */
 	public function multi_resize( $sizes ) {
 		$metadata = array();
@@ -272,11 +280,20 @@ class WP_Image_Editor_Imagick extends WP_Image_Editor {
 			if ( ! $this->image )
 				$this->image = $orig_image->getImage();
 
-			if ( ! ( isset( $size_data['width'] ) && isset( $size_data['height'] ) ) )
+			if ( ! isset( $size_data['width'] ) && ! isset( $size_data['height'] ) ) {
 				continue;
+			}
 
-			if ( ! isset( $size_data['crop'] ) )
+			if ( ! isset( $size_data['width'] ) ) {
+				$size_data['width'] = null;
+			}
+			if ( ! isset( $size_data['height'] ) ) {
+				$size_data['height'] = null;
+			}
+
+			if ( ! isset( $size_data['crop'] ) ) {
 				$size_data['crop'] = false;
+			}
 
 			$resize_result = $this->resize( $size_data['width'], $size_data['height'], $size_data['crop'] );
 
diff --git a/src/wp-includes/class-wp-image-editor.php b/src/wp-includes/class-wp-image-editor.php
index 7f6488f91f..5affba48c7 100644
--- a/src/wp-includes/class-wp-image-editor.php
+++ b/src/wp-includes/class-wp-image-editor.php
@@ -82,13 +82,17 @@ abstract class WP_Image_Editor {
 	/**
 	 * Resizes current image.
 	 *
+	 * At minimum, either a height or width must be provided.
+	 * If one of the two is set to null, the resize will
+	 * maintain aspect ratio according to the provided dimension.
+	 *
 	 * @since 3.5.0
 	 * @access public
 	 * @abstract
 	 *
-	 * @param int $max_w
-	 * @param int $max_h
-	 * @param boolean $crop
+	 * @param  int|null $max_w Image width.
+	 * @param  int|null $max_h Image height.
+	 * @param  boolean  $crop
 	 * @return boolean|WP_Error
 	 */
 	abstract public function resize( $max_w, $max_h, $crop = false );
diff --git a/tests/phpunit/tests/image/base.php b/tests/phpunit/tests/image/base.php
index 26f3b59d9a..be9ab67350 100644
--- a/tests/phpunit/tests/image/base.php
+++ b/tests/phpunit/tests/image/base.php
@@ -39,12 +39,35 @@ abstract class WP_Image_UnitTestCase extends WP_UnitTestCase {
 	 * @param  int $alpha
 	 */
 	protected function assertImageAlphaAtPoint( $image_path, $point, $alpha ) {
-
 		$im = imagecreatefrompng( $image_path );
-		$rgb = imagecolorat($im, $point[0], $point[1]);
+		$rgb = imagecolorat( $im, $point[0], $point[1] );
 
-		$colors = imagecolorsforindex($im, $rgb);
+		$colors = imagecolorsforindex( $im, $rgb );
 
 		$this->assertEquals( $alpha, $colors['alpha'] );
 	}
+
+	/**
+	 * Helper assertion to check actual image dimensions on disk
+	 *
+	 * @param string $filename Image filename.
+	 * @param int    $width    Width to verify.
+	 * @param int    $height   Height to verify.
+	 */
+	protected function assertImageDimensions( $filename, $width, $height ) {
+		$detected_width = 0;
+		$detected_height = 0;
+		$image_size = @getimagesize( $filename );
+
+		if ( isset( $image_size[0] ) ) {
+			$detected_width = $image_size[0];
+		}
+
+		if ( isset( $image_size[1] ) ) {
+			$detected_height = $image_size[1];
+		}
+
+		$this->assertEquals( $width, $detected_width );
+		$this->assertEquals( $height, $detected_height );
+	}
 }
diff --git a/tests/phpunit/tests/image/editor_gd.php b/tests/phpunit/tests/image/editor_gd.php
index f5fdd99651..ca134bdb39 100644
--- a/tests/phpunit/tests/image/editor_gd.php
+++ b/tests/phpunit/tests/image/editor_gd.php
@@ -8,17 +8,28 @@
  */
 
 class Tests_Image_Editor_GD extends WP_Image_UnitTestCase {
+
 	public $editor_engine = 'WP_Image_Editor_GD';
 
-	public function setup() {
+	public function setUp() {
 		require_once( ABSPATH . WPINC . '/class-wp-image-editor.php' );
 		require_once( ABSPATH . WPINC . '/class-wp-image-editor-gd.php' );
+
 		parent::setUp();
 	}
 
+	public function shutDown() {
+		$folder = DIR_TESTDATA . '/images/waffles-*.jpg';
+
+		foreach ( glob( $folder ) as $file ) {
+			unlink( $file );
+		}
+
+		parent::shutDown();
+	}
+
 	/**
 	 * Check support for GD compatible mime types.
-	 * 
 	 */
 	public function test_supports_mime_type() {
 		$gd_image_editor = new WP_Image_Editor_GD( null );
@@ -30,41 +41,362 @@ class Tests_Image_Editor_GD extends WP_Image_UnitTestCase {
 
 	/**
 	 * Test resizing an image, not using crop
-	 * 
 	 */
 	public function test_resize() {
-
-		$file = DIR_TESTDATA . '/images/gradient-square.jpg';
+		$file = DIR_TESTDATA . '/images/waffles.jpg';
 
 		$gd_image_editor = new WP_Image_Editor_GD( $file );
 		$gd_image_editor->load();
 
 		$gd_image_editor->resize( 100, 50 );
 
-		$this->assertEquals( array( 'width' => 50, 'height' => 50 ), $gd_image_editor->get_size() );
+		$this->assertEquals(
+			array(
+				'width'  => 75,
+				'height' => 50,
+			),
+			$gd_image_editor->get_size()
+		);
 	}
 
 	/**
-	 * Test resizing an image including cropping
-	 * 
+	 * Test multi_resize with single image resize and no crop
+	 */
+	public function test_single_multi_resize() {
+		$file = DIR_TESTDATA . '/images/waffles.jpg';
+
+		$gd_image_editor = new WP_Image_Editor_GD( $file );
+		$gd_image_editor->load();
+
+		$sizes_array =	array(
+			array(
+				'width'  => 50,
+				'height' => 50,
+			),
+		);
+
+		$resized = $gd_image_editor->multi_resize( $sizes_array );
+
+		# First, check to see if returned array is as expected
+		$expected_array = array(
+			array(
+				'file'      => 'waffles-50x33.jpg',
+				'width'     => 50,
+				'height'    => 33,
+				'mime-type' => 'image/jpeg',
+			),
+		);
+
+		$this->assertEquals( $expected_array, $resized );
+
+		// Now, verify real dimensions are as expected
+		$image_path = DIR_TESTDATA . '/images/'. $resized[0]['file'];
+		$this->assertImageDimensions(
+			$image_path,
+			$expected_array[0]['width'],
+			$expected_array[0]['height']
+		);
+	}
+
+	/**
+	 * Ensure multi_resize doesn't create an image when
+	 * both height and weight are missing, null, or 0.
+	 *
+	 * ticket 26823
+	 */
+	public function test_multi_resize_does_not_create() {
+		$file = DIR_TESTDATA . '/images/waffles.jpg';
+
+		$gd_image_editor = new WP_Image_Editor_GD( $file );
+		$gd_image_editor->load();
+
+		$sizes_array = array(
+			array(
+				'width'  => 0,
+				'height' => 0,
+			),
+			array(
+				'width'  => 0,
+				'height' => 0,
+				'crop'   => true,
+			),
+			array(
+				'width'  => null,
+				'height' => null,
+			),
+			array(
+				'width'  => null,
+				'height' => null,
+				'crop'   => true,
+			),
+			array(
+				'width'  => '',
+				'height' => '',
+			),
+			array(
+				'width'  => '',
+				'height' => '',
+				'crop'   => true,
+			),
+			array(
+				'width'  => 0,
+			),
+			array(
+				'width'  => 0,
+				'crop'   => true,
+			),
+			array(
+				'width'  => null,
+			),
+			array(
+				'width'  => null,
+				'crop'   => true,
+			),
+			array(
+				'width'  => '',
+			),
+			array(
+				'width'  => '',
+				'crop'   => true,
+			),
+		);
+
+		$resized = $gd_image_editor->multi_resize( $sizes_array );
+
+		// If no images are generated, the returned array is empty.
+		$this->assertEmpty( $resized );
+	}
+
+	/**
+	 * Test multi_resize with multiple sizes
+	 *
+	 * ticket 26823
+	 */
+	public function test_multi_resize() {
+		$file = DIR_TESTDATA . '/images/waffles.jpg';
+
+		$gd_image_editor = new WP_Image_Editor_GD( $file );
+		$gd_image_editor->load();
+
+		$sizes_array = array(
+
+			/**
+			 * #0 - 10x10 resize, no cropping.
+			 * By aspect, should be 10x6 output.
+			 */
+			array(
+				'width'  => 10,
+				'height' => 10,
+				'crop'   => false,
+			),
+
+			/**
+			 * #1 - 75x50 resize, with cropping.
+			 * Output dimensions should be 75x50
+			 */
+			array(
+				'width'  => 75,
+				'height' => 50,
+				'crop'   => true,
+			),
+
+			/**
+			 * #2 - 20 pixel max height, no cropping.
+			 * By aspect, should be 30x20 output.
+			 */
+			array(
+				'width'  => 9999, # Arbitrary High Value
+				'height' => 20,
+				'crop'   => false,
+			),
+
+			/**
+			 * #3 - 45 pixel max height, with cropping.
+			 * By aspect, should be 45x400 output.
+			 */
+			array(
+				'width'  => 45,
+				'height' => 9999, # Arbitrary High Value
+				'crop'   => true,
+			),
+
+			/**
+			 * #4 - 50 pixel max width, no cropping.
+			 * By aspect, should be 50x33 output.
+			 */
+			array(
+				'width' => 50,
+			),
+
+			/**
+			 * #5 - 55 pixel max width, no cropping, null height
+			 * By aspect, should be 55x36 output.
+			 */
+			array(
+				'width'  => 55,
+				'height' => null,
+			),
+
+			/**
+			 * #6 - 55 pixel max height, no cropping, no width specified.
+			 * By aspect, should be 82x55 output.
+			 */
+			array(
+				'height' => 55,
+			),
+
+			/**
+			 * #7 - 60 pixel max height, no cropping, null width.
+			 * By aspect, should be 90x60 output.
+			 */
+			array(
+				'width'  => null,
+				'height' => 60,
+			),
+
+			/**
+			 * #8 - 70 pixel max height, no cropping, negative width.
+			 * By aspect, should be 105x70 output.
+			 */
+			array(
+				'width'  => -9999, # Arbitrary Negative Value
+				'height' => 70,
+			),
+
+			/**
+			 * #9 - 200 pixel max width, no cropping, negative height.
+			 * By aspect, should be 200x133 output.
+			 */
+			array(
+				'width'  => 200,
+				'height' => -9999, # Arbitrary Negative Value
+			),
+		);
+
+		$resized = $gd_image_editor->multi_resize( $sizes_array );
+
+		$expected_array = array(
+
+			// #0
+			array(
+				'file'      => 'waffles-10x6.jpg',
+				'width'     => 10,
+				'height'    => 6,
+				'mime-type' => 'image/jpeg',
+			),
+
+			// #1
+			array(
+				'file'      => 'waffles-75x50.jpg',
+				'width'     => 75,
+				'height'    => 50,
+				'mime-type' => 'image/jpeg',
+			),
+
+			// #2
+			array(
+				'file'      => 'waffles-30x20.jpg',
+				'width'     => 30,
+				'height'    => 20,
+				'mime-type' => 'image/jpeg',
+			),
+
+			// #3
+			array(
+				'file'      => 'waffles-45x400.jpg',
+				'width'     => 45,
+				'height'    => 400,
+				'mime-type' => 'image/jpeg',
+			),
+
+			// #4
+			array(
+				'file'      => 'waffles-50x33.jpg',
+				'width'     => 50,
+				'height'    => 33,
+				'mime-type' => 'image/jpeg',
+			),
+
+			// #5
+			array(
+				'file'      => 'waffles-55x36.jpg',
+				'width'     => 55,
+				'height'    => 36,
+				'mime-type' => 'image/jpeg',
+			),
+
+			// #6
+			array(
+				'file'      => 'waffles-82x55.jpg',
+				'width'     => 82,
+				'height'    => 55,
+				'mime-type' => 'image/jpeg',
+			),
+
+			// #7
+			array(
+				'file'      => 'waffles-90x60.jpg',
+				'width'     => 90,
+				'height'    => 60,
+				'mime-type' => 'image/jpeg',
+			),
+
+			// #8
+			array(
+				'file'      => 'waffles-105x70.jpg',
+				'width'     => 105,
+				'height'    => 70,
+				'mime-type' => 'image/jpeg',
+			),
+
+			// #9
+			array(
+				'file'      => 'waffles-200x133.jpg',
+				'width'     => 200,
+				'height'    => 133,
+				'mime-type' => 'image/jpeg',
+			),
+		);
+
+		$this->assertNotNull( $resized );
+		$this->assertEquals( $expected_array, $resized );
+
+		foreach( $resized as $key => $image_data ){
+			$image_path = DIR_TESTDATA . '/images/' . $image_data['file'];
+
+			// Now, verify real dimensions are as expected
+			$this->assertImageDimensions(
+				$image_path,
+				$expected_array[$key]['width'],
+				$expected_array[$key]['height']
+			);
+		}
+	}
+
+	/**
+	 * Test resizing an image with cropping
 	 */
 	public function test_resize_and_crop() {
-
-		$file = DIR_TESTDATA . '/images/gradient-square.jpg';
+		$file = DIR_TESTDATA . '/images/waffles.jpg';
 
 		$gd_image_editor = new WP_Image_Editor_GD( $file );
 		$gd_image_editor->load();
 
 		$gd_image_editor->resize( 100, 50, true );
 
-		$this->assertEquals( array( 'width' => 100, 'height' => 50 ), $gd_image_editor->get_size() );
+		$this->assertEquals(
+			array(
+				'width'  => 100,
+				'height' => 50,
+			),
+			$gd_image_editor->get_size()
+		);
 	}
 
 	/**
 	 * Test cropping an image
 	 */
 	public function test_crop() {
-
 		$file = DIR_TESTDATA . '/images/gradient-square.jpg';
 
 		$gd_image_editor = new WP_Image_Editor_GD( $file );
@@ -72,15 +404,19 @@ class Tests_Image_Editor_GD extends WP_Image_UnitTestCase {
 
 		$gd_image_editor->crop( 0, 0, 50, 50 );
 
-		$this->assertEquals( array( 'width' => 50, 'height' => 50 ), $gd_image_editor->get_size() );
-
+		$this->assertEquals(
+			array(
+				'width' => 50,
+				'height' => 50,
+			),
+			$gd_image_editor->get_size()
+		);
 	}
 
 	/**
 	 * Test rotating an image 180 deg
 	 */
 	public function test_rotate() {
-
 		$file = DIR_TESTDATA . '/images/gradient-square.jpg';
 
 		$gd_image_editor = new WP_Image_Editor_GD( $file );
@@ -100,7 +436,6 @@ class Tests_Image_Editor_GD extends WP_Image_UnitTestCase {
 	 * Test flipping an image
 	 */
 	public function test_flip() {
-
 		$file = DIR_TESTDATA . '/images/gradient-square.jpg';
 
 		$gd_image_editor = new WP_Image_Editor_GD( $file );
@@ -117,42 +452,38 @@ class Tests_Image_Editor_GD extends WP_Image_UnitTestCase {
 	}
 
 	/**
-	 * Test the image created with WP_Image_Edior_GD preserves alpha when resizing
-	 * 
+	 * Test the image created with WP_Image_Editor_GD preserves alpha when resizing
+	 *
 	 * @ticket 23039
 	 */
 	public function test_image_preserves_alpha_on_resize() {
-
 		$file = DIR_TESTDATA . '/images/transparent.png';
 
 		$editor = wp_get_image_editor( $file );
 		$editor->load();
-		$editor->resize(5,5);
+		$editor->resize( 5, 5 );
 		$save_to_file = tempnam( get_temp_dir(), '' ) . '.png';
-		
+
 		$editor->save( $save_to_file );
 
 		$this->assertImageAlphaAtPoint( $save_to_file, array( 0,0 ), 127 );
-
 	}
-	
+
 	/**
-	 * Test the image created with WP_Image_Edior_GD preserves alpha with no resizing etc
-	 * 
+	 * Test the image created with WP_Image_Editor_GD preserves alpha with no resizing etc
+	 *
 	 * @ticket 23039
 	 */
 	public function test_image_preserves_alpha() {
-
 		$file = DIR_TESTDATA . '/images/transparent.png';
 
 		$editor = wp_get_image_editor( $file );
 		$editor->load();
 
 		$save_to_file = tempnam( get_temp_dir(), '' ) . '.png';
-		
+
 		$editor->save( $save_to_file );
 
 		$this->assertImageAlphaAtPoint( $save_to_file, array( 0,0 ), 127 );
 	}
-
 }
diff --git a/tests/phpunit/tests/image/editor_imagick.php b/tests/phpunit/tests/image/editor_imagick.php
index 1e43298a54..ec0cd23dec 100644
--- a/tests/phpunit/tests/image/editor_imagick.php
+++ b/tests/phpunit/tests/image/editor_imagick.php
@@ -11,24 +11,27 @@ class Tests_Image_Editor_Imagick extends WP_Image_UnitTestCase {
 
 	public $editor_engine = 'WP_Image_Editor_Imagick';
 
-	public function setup() {
+	public function setUp() {
 		require_once( ABSPATH . WPINC . '/class-wp-image-editor.php' );
 		require_once( ABSPATH . WPINC . '/class-wp-image-editor-imagick.php' );
 
-		$editor = new WP_Image_Editor_Imagick( null );
-
-		if ( ! $editor->test() )
-			$this->markTestSkipped( 'Image Magick not available' );
-
 		parent::setUp();
 	}
 
+	public function shutDown() {
+		$folder = DIR_TESTDATA . '/images/waffles-*.jpg';
+
+		foreach ( glob( $folder ) as $file ) {
+			unlink( $file );
+		}
+
+		parent::shutDown();
+	}
+
 	/**
-	 * Check support for Image Magick compatible mime types.
-	 * 
+	 * Check support for ImageMagick compatible mime types.
 	 */
 	public function test_supports_mime_type() {
-
 		$imagick_image_editor = new WP_Image_Editor_Imagick( null );
 
 		$this->assertTrue( $imagick_image_editor->supports_mime_type( 'image/jpeg' ), 'Does not support image/jpeg' );
@@ -38,41 +41,362 @@ class Tests_Image_Editor_Imagick extends WP_Image_UnitTestCase {
 
 	/**
 	 * Test resizing an image, not using crop
-	 * 
 	 */
 	public function test_resize() {
-
-		$file = DIR_TESTDATA . '/images/gradient-square.jpg';
+		$file = DIR_TESTDATA . '/images/waffles.jpg';
 
 		$imagick_image_editor = new WP_Image_Editor_Imagick( $file );
 		$imagick_image_editor->load();
 
 		$imagick_image_editor->resize( 100, 50 );
 
-		$this->assertEquals( array( 'width' => 50, 'height' => 50 ), $imagick_image_editor->get_size() );
+		$this->assertEquals(
+			array(
+				'width'  => 75,
+				'height' => 50,
+			),
+			$imagick_image_editor->get_size()
+		);
 	}
 
 	/**
-	 * Test resizing an image including cropping
-	 * 
+	 * Test multi_resize with single image resize and no crop
+	 */
+	public function test_single_multi_resize() {
+		$file = DIR_TESTDATA . '/images/waffles.jpg';
+
+		$imagick_image_editor = new WP_Image_Editor_Imagick( $file );
+		$imagick_image_editor->load();
+
+		$sizes_array =	array(
+			array(
+				'width'  => 50,
+				'height' => 50,
+			),
+		);
+
+		$resized = $imagick_image_editor->multi_resize( $sizes_array );
+
+		# First, check to see if returned array is as expected
+		$expected_array = array(
+			array(
+				'file'      => 'waffles-50x33.jpg',
+				'width'     => 50,
+				'height'    => 33,
+				'mime-type' => 'image/jpeg',
+			),
+		);
+
+		$this->assertEquals( $expected_array, $resized );
+
+		// Now, verify real dimensions are as expected
+		$image_path = DIR_TESTDATA . '/images/'. $resized[0]['file'];
+		$this->assertImageDimensions(
+			$image_path,
+			$expected_array[0]['width'],
+			$expected_array[0]['height']
+		);
+	}
+
+	/**
+	 * Ensure multi_resize doesn't create an image when
+	 * both height and weight are missing, null, or 0.
+	 *
+	 * ticket 26823
+	 */
+	public function test_multi_resize_does_not_create() {
+		$file = DIR_TESTDATA . '/images/waffles.jpg';
+
+		$imagick_image_editor = new WP_Image_Editor_Imagick( $file );
+		$imagick_image_editor->load();
+
+		$sizes_array = array(
+			array(
+				'width'  => 0,
+				'height' => 0,
+			),
+			array(
+				'width'  => 0,
+				'height' => 0,
+				'crop'   => true,
+			),
+			array(
+				'width'  => null,
+				'height' => null,
+			),
+			array(
+				'width'  => null,
+				'height' => null,
+				'crop'   => true,
+			),
+			array(
+				'width'  => '',
+				'height' => '',
+			),
+			array(
+				'width'  => '',
+				'height' => '',
+				'crop'   => true,
+			),
+			array(
+				'width'  => 0,
+			),
+			array(
+				'width'  => 0,
+				'crop'   => true,
+			),
+			array(
+				'width'  => null,
+			),
+			array(
+				'width'  => null,
+				'crop'   => true,
+			),
+			array(
+				'width'  => '',
+			),
+			array(
+				'width'  => '',
+				'crop'   => true,
+			),
+		);
+
+		$resized = $imagick_image_editor->multi_resize( $sizes_array );
+
+		// If no images are generated, the returned array is empty.
+		$this->assertEmpty( $resized );
+	}
+
+	/**
+	 * Test multi_resize with multiple sizes
+	 *
+	 * ticket 26823
+	 */
+	public function test_multi_resize() {
+		$file = DIR_TESTDATA . '/images/waffles.jpg';
+
+		$imagick_image_editor = new WP_Image_Editor_Imagick( $file );
+		$imagick_image_editor->load();
+
+		$sizes_array = array(
+
+			/**
+			 * #0 - 10x10 resize, no cropping.
+			 * By aspect, should be 10x6 output.
+			 */
+			array(
+				'width'  => 10,
+				'height' => 10,
+				'crop'   => false,
+			),
+
+			/**
+			 * #1 - 75x50 resize, with cropping.
+			 * Output dimensions should be 75x50
+			 */
+			array(
+				'width'  => 75,
+				'height' => 50,
+				'crop'   => true,
+			),
+
+			/**
+			 * #2 - 20 pixel max height, no cropping.
+			 * By aspect, should be 30x20 output.
+			 */
+			array(
+				'width'  => 9999, # Arbitrary High Value
+				'height' => 20,
+				'crop'   => false,
+			),
+
+			/**
+			 * #3 - 45 pixel max height, with cropping.
+			 * By aspect, should be 45x400 output.
+			 */
+			array(
+				'width'  => 45,
+				'height' => 9999, # Arbitrary High Value
+				'crop'   => true,
+			),
+
+			/**
+			 * #4 - 50 pixel max width, no cropping.
+			 * By aspect, should be 50x33 output.
+			 */
+			array(
+				'width' => 50,
+			),
+
+			/**
+			 * #5 - 55 pixel max width, no cropping, null height
+			 * By aspect, should be 55x36 output.
+			 */
+			array(
+				'width'  => 55,
+				'height' => null,
+			),
+
+			/**
+			 * #6 - 55 pixel max height, no cropping, no width specified.
+			 * By aspect, should be 82x55 output.
+			 */
+			array(
+				'height' => 55,
+			),
+
+			/**
+			 * #7 - 60 pixel max height, no cropping, null width.
+			 * By aspect, should be 90x60 output.
+			 */
+			array(
+				'width'  => null,
+				'height' => 60,
+			),
+
+			/**
+			 * #8 - 70 pixel max height, no cropping, negative width.
+			 * By aspect, should be 105x70 output.
+			 */
+			array(
+				'width'  => -9999, # Arbitrary Negative Value
+				'height' => 70,
+			),
+
+			/**
+			 * #9 - 200 pixel max width, no cropping, negative height.
+			 * By aspect, should be 200x133 output.
+			 */
+			array(
+				'width'  => 200,
+				'height' => -9999, # Arbitrary Negative Value
+			),
+		);
+
+		$resized = $imagick_image_editor->multi_resize( $sizes_array );
+
+		$expected_array = array(
+
+			// #0
+			array(
+				'file'      => 'waffles-10x6.jpg',
+				'width'     => 10,
+				'height'    => 6,
+				'mime-type' => 'image/jpeg',
+			),
+
+			// #1
+			array(
+				'file'      => 'waffles-75x50.jpg',
+				'width'     => 75,
+				'height'    => 50,
+				'mime-type' => 'image/jpeg',
+			),
+
+			// #2
+			array(
+				'file'      => 'waffles-30x20.jpg',
+				'width'     => 30,
+				'height'    => 20,
+				'mime-type' => 'image/jpeg',
+			),
+
+			// #3
+			array(
+				'file'      => 'waffles-45x400.jpg',
+				'width'     => 45,
+				'height'    => 400,
+				'mime-type' => 'image/jpeg',
+			),
+
+			// #4
+			array(
+				'file'      => 'waffles-50x33.jpg',
+				'width'     => 50,
+				'height'    => 33,
+				'mime-type' => 'image/jpeg',
+			),
+
+			// #5
+			array(
+				'file'      => 'waffles-55x36.jpg',
+				'width'     => 55,
+				'height'    => 36,
+				'mime-type' => 'image/jpeg',
+			),
+
+			// #6
+			array(
+				'file'      => 'waffles-82x55.jpg',
+				'width'     => 82,
+				'height'    => 55,
+				'mime-type' => 'image/jpeg',
+			),
+
+			// #7
+			array(
+				'file'      => 'waffles-90x60.jpg',
+				'width'     => 90,
+				'height'    => 60,
+				'mime-type' => 'image/jpeg',
+			),
+
+			// #8
+			array(
+				'file'      => 'waffles-105x70.jpg',
+				'width'     => 105,
+				'height'    => 70,
+				'mime-type' => 'image/jpeg',
+			),
+
+			// #9
+			array(
+				'file'      => 'waffles-200x133.jpg',
+				'width'     => 200,
+				'height'    => 133,
+				'mime-type' => 'image/jpeg',
+			),
+		);
+
+		$this->assertNotNull( $resized );
+		$this->assertEquals( $expected_array, $resized );
+
+		foreach( $resized as $key => $image_data ){
+			$image_path = DIR_TESTDATA . '/images/' . $image_data['file'];
+
+			// Now, verify real dimensions are as expected
+			$this->assertImageDimensions(
+				$image_path,
+				$expected_array[$key]['width'],
+				$expected_array[$key]['height']
+			);
+		}
+	}
+
+	/**
+	 * Test resizing an image with cropping
 	 */
 	public function test_resize_and_crop() {
-
-		$file = DIR_TESTDATA . '/images/gradient-square.jpg';
+		$file = DIR_TESTDATA . '/images/waffles.jpg';
 
 		$imagick_image_editor = new WP_Image_Editor_Imagick( $file );
 		$imagick_image_editor->load();
 
 		$imagick_image_editor->resize( 100, 50, true );
 
-		$this->assertEquals( array( 'width' => 100, 'height' => 50 ), $imagick_image_editor->get_size() );
+		$this->assertEquals(
+			array(
+				'width'  => 100,
+				'height' => 50,
+			),
+			$imagick_image_editor->get_size()
+		);
 	}
 
 	/**
 	 * Test cropping an image
 	 */
 	public function test_crop() {
-
 		$file = DIR_TESTDATA . '/images/gradient-square.jpg';
 
 		$imagick_image_editor = new WP_Image_Editor_Imagick( $file );
@@ -80,15 +404,19 @@ class Tests_Image_Editor_Imagick extends WP_Image_UnitTestCase {
 
 		$imagick_image_editor->crop( 0, 0, 50, 50 );
 
-		$this->assertEquals( array( 'width' => 50, 'height' => 50 ), $imagick_image_editor->get_size() );
-
+		$this->assertEquals(
+			array(
+				'width' => 50,
+				'height' => 50,
+			),
+			$imagick_image_editor->get_size()
+		);
 	}
 
 	/**
 	 * Test rotating an image 180 deg
 	 */
 	public function test_rotate() {
-
 		$file = DIR_TESTDATA . '/images/gradient-square.jpg';
 
 		$imagick_image_editor = new WP_Image_Editor_Imagick( $file );
@@ -108,7 +436,6 @@ class Tests_Image_Editor_Imagick extends WP_Image_UnitTestCase {
 	 * Test flipping an image
 	 */
 	public function test_flip() {
-
 		$file = DIR_TESTDATA . '/images/gradient-square.jpg';
 
 		$imagick_image_editor = new WP_Image_Editor_Imagick( $file );
@@ -125,39 +452,36 @@ class Tests_Image_Editor_Imagick extends WP_Image_UnitTestCase {
 	}
 
 	/**
-	 * Test the image created with WP_Image_Edior_Imagick preserves alpha when resizing
+	 * Test the image created with WP_Image_Editor_Imagick preserves alpha when resizing
 	 *
 	 * @ticket 24871
 	 */
 	public function test_image_preserves_alpha_on_resize() {
-
 		$file = DIR_TESTDATA . '/images/transparent.png';
 
 		$editor = wp_get_image_editor( $file );
 		$editor->load();
-		$editor->resize(5,5);
+		$editor->resize( 5, 5 );
 		$save_to_file = tempnam( get_temp_dir(), '' ) . '.png';
 		
 		$editor->save( $save_to_file );
 
 		$this->assertImageAlphaAtPoint( $save_to_file, array( 0,0 ), 127 );
-
 	}
-	
+
 	/**
-	 * Test the image created with WP_Image_Edior_Imagick preserves alpha with no resizing etc
+	 * Test the image created with WP_Image_Editor_Imagick preserves alpha with no resizing etc
 	 *
 	 * @ticket 24871
 	 */
 	public function test_image_preserves_alpha() {
-
 		$file = DIR_TESTDATA . '/images/transparent.png';
 
 		$editor = wp_get_image_editor( $file );
 		$editor->load();
 
 		$save_to_file = tempnam( get_temp_dir(), '' ) . '.png';
-		
+
 		$editor->save( $save_to_file );
 
 		$this->assertImageAlphaAtPoint( $save_to_file, array( 0,0 ), 127 );