Ticket #43741: 43742.2.diff

src/wp-admin/includes/media.php

@@ -924 +924 @@
                 // Set variables for storage, fix file filename for query strings.
                 preg_match( '/[^\?]+\.(jpe?g|jpe|gif|png)\b/i', $file, $matches );
                 if ( ! $matches ) {
-                        return new WP_Error( 'image_sideload_failed', __( 'Invalid image URL' ) );
+                        $extension = wp_get_image_mime( $file );
+                        if ( $extension !== false ) {
+                                if ( preg_match( '/(jpe?g|jpe|gif|png)/i', $extension, $ext_matches ) ) {
+                                        $matches = array( '.' . $ext_matches[0] );
+                                }
+                        } else {
+                                return new WP_Error( 'image_sideload_failed', __( 'Invalid image URL' ) );
+                        }
                 }
 
                 $file_array         = array();