Ticket #45363: 45363_1.diff

wp-admin/includes/image.php

@@ -160 +160 @@
                 $metadata = wp_read_audio_metadata( $file );
                 $support  = current_theme_supports( 'post-thumbnails', 'attachment:audio' ) || post_type_supports( 'attachment:audio', 'thumbnail' );
         }
+        
+        /**
+         * Filters the mime types that have support for thumbnail generation
+         *
+         * @param array $other_supported_mime_types  An array of supported MIME types
+         */
+        $other_supported_mime_types = apply_filters( 'mime_types_thumbnail_generation', array( 'application/pdf' ) );
 
         if ( $support && ! empty( $metadata['image']['data'] ) ) {
                 // Check for existing cover.
@@ -216 +223 @@
                         }
                 }
         } // Try to create image thumbnails for PDFs
-        elseif ( 'application/pdf' === $mime_type ) {
+        elseif ( in_array( $mime_type, $other_supported_mime_types, true ) ) {
                 $fallback_sizes = array(
                         'thumbnail',
                         'medium',