diff --git a/libvips/foreign/analyze2vips.c b/libvips/foreign/analyze2vips.c
index 489d036f..c3802d8c 100644
--- a/libvips/foreign/analyze2vips.c
+++ b/libvips/foreign/analyze2vips.c
@@ -241,7 +241,7 @@ getstr( int mx, const char *str )
 
 	g_assert( mx < 256 );
 
-	strncpy( buf, str, mx );
+	vips_strncpy( buf, str, mx );
 	buf[mx]= '\0';
 
 	/* How annoying, patient_id has some funny ctrlchars in that mess up
diff --git a/libvips/foreign/vipspng.c b/libvips/foreign/vipspng.c
index 78301f44..89c65b50 100644
--- a/libvips/foreign/vipspng.c
+++ b/libvips/foreign/vipspng.c
@@ -71,8 +71,6 @@
  * 	- support png8 palette write with palette, colours, Q, dither
  * 25/8/18
  * 	- support xmp read/write
- * 21/11/18
- * 	- save xmp as string, not blob
  */
 
 /*
@@ -277,18 +275,25 @@ vips__set_text( VipsImage *out, int i, const char *key, const char *text )
 {
 	char name[256];
 
-	if( strcmp( key, "XML:com.adobe.xmp") == 0 ) 
-		/* Save as an XMP tag.
+	if( strcmp( key, "XML:com.adobe.xmp" ) == 0 ) {
+		/* Save as an XMP tag. This must be a BLOB, for compatibility
+		 * for things like the XMP blob that the tiff loader adds.
+		 *
+		 * Note that this will remove the null-termination from the
+		 * string. We must carefully reattach this.
 		 */
-		strncpy( name, VIPS_META_XMP_NAME, 256 );
-	else 
-		/* Save as a comment. Some PNGs have EXIF data as
+		vips_image_set_blob_copy( out, 
+			VIPS_META_XMP_NAME, text, strlen( text ) );
+	}
+	else  {
+		/* Save as a string comment. Some PNGs have EXIF data as
 		 * text segments, but the correct way to support this is with
 		 * png_get_eXIf_1().
 		 */
 		vips_snprintf( name, 256, "png-comment-%d-%s", i, key );
 
-	vips_image_set_string( out, name, text );
+		vips_image_set_string( out, name, text );
+	}
 
 	return( 0 );
 }
@@ -1098,12 +1103,22 @@ write_vips( Write *write,
 	}
 
 	if( vips_image_get_typeof( in, VIPS_META_XMP_NAME ) ) {
-		const char *str;
+		void *data;
+		size_t length;
+		char *str;
 
-		if( vips_image_get_string( in, VIPS_META_XMP_NAME, &str ) )
+		/* XMP is attached as a BLOB with no null-termination. We
+		 * must re-add this.
+		 */
+		if( vips_image_get_blob( in, 
+			VIPS_META_XMP_NAME, &data, &length ) )
 			return( -1 );
+
+		str = g_malloc( length + 1 );
+		vips_strncpy( str, data, length + 1 );
 		vips__png_set_text( write->pPng, write->pInfo, 
 			"XML:com.adobe.xmp", str );
+		g_free( str );
 	}
 
 	/* Set any "png-comment-xx-yyy" metadata items.
diff --git a/libvips/iofuncs/buf.c b/libvips/iofuncs/buf.c
index c371d439..08b9b5d4 100644
--- a/libvips/iofuncs/buf.c
+++ b/libvips/iofuncs/buf.c
@@ -279,7 +279,7 @@ vips_buf_appendns( VipsBuf *buf, const char *str, int sz )
 	 */
 	cpy = VIPS_MIN( n, avail );
 
-	strncpy( buf->base + buf->i, str, cpy );
+	vips_strncpy( buf->base + buf->i, str, cpy );
 	buf->i += cpy;
 
 	if( buf->i >= buf->mx - 4 ) {
diff --git a/test/test-suite/test_foreign.py b/test/test-suite/test_foreign.py
index e273e7fc..c4383437 100644
--- a/test/test-suite/test_foreign.py
+++ b/test/test-suite/test_foreign.py
@@ -241,7 +241,6 @@ class TestForeign:
             assert im.width == 290
             assert im.height == 442
             assert im.bands == 3
-            assert im.get("xmp-data") == "sample xmp string"
 
         self.file_loader("pngload", PNG_FILE, png_valid)
         self.buffer_loader("pngload_buffer", PNG_FILE, png_valid)