Ticket #33979: 33979.diff

wp-includes/media.php

@@ -1645 +1645 @@
                 if ( isset( $image_meta['height'], $image_meta['width'] ) ) {
                         $orientation = ( $image_meta['height'] > $image_meta['width'] ) ? 'portrait' : 'landscape';
                 }
-                $output .= "<{$itemtag} class='gallery-item'>";
+
+                /**
+                 * Filter the gallery item classes.
+                 *
+                 * @since 4.4
+                 *
+                 * @param string $classes    Classes applied to gallery item.
+                 * @param object $attachment Attachment object.
+                 */
+                $classes = 'gallery-item';
+                $gallery_item_classes = apply_filters( 'gallery_item_classes', $classes, $attachment );
+                $output .= "<{$itemtag} class='{$gallery_item_classes}'>";
                 $output .= "
                         <{$icontag} class='gallery-icon {$orientation}'>
                                 $image_output