Dev tools: Add `grunt imagemin:core` task for optimizing images pre-commit.

Adds grunt-contrib-imagemin, so an `npm install` will be required.

props jorbin, wonderboymusic for initial patches.
see #25169.


git-svn-id: https://develop.svn.wordpress.org/trunk@27172 602fd350-edb4-49c9-b593-d223f7449a82

Gruntfile.js

@@ -303,7 +303,7 @@ module.exports = function(grunt) {
 			}
 		},
 		jsvalidate:{
-			options:{
+			options: {
 				globals: {},
 				esprimaOptions:{},
 				verbose: false
@@ -317,6 +317,17 @@ module.exports = function(grunt) {
 				}
 			}
 		},
+		imagemin: {
+			core: {
+				expand: true,
+				cwd: SOURCE_DIR,
+				src: [
+					'wp-{admin,includes}/images/**/*.{png,jpg,gif,jpeg}',
+					'wp-includes/js/tinymce/skins/wordpress/images/*.{png,jpg,gif,jpeg}'
+				],
+				dest: SOURCE_DIR
+			}
+		},
 		watch: {
 			all: {
 				files: [

package.json

@@ -22,6 +22,7 @@
     "grunt-cssjanus": "~0.2.2",
     "grunt-sass": "~0.10.0",
     "grunt-jsvalidate": "~0.2.2",
+    "grunt-contrib-imagemin" : "~0.4.1",
     "matchdep": "~0.3.0"
   }
 }