+ // For 404 handled thumbnails, we only use the the base name of the URI
+ // for the thumb params and the parent directory for the source file name.
+ // Check that the zone relative path matches up so squid caches won't pick
+ // up thumbs that would not be purged on source file deletion (bug 34231).
+ if ( isset( $params['rel404'] ) // thumbnail was handled via 404
+ && urldecode( $params['rel404'] ) !== $img->getThumbRel( $thumbName ) )
+ {
+ wfThumbError( 404, 'The source file for the specified thumbnail does not exist.' );
+ wfProfileOut( __METHOD__ );
+ return;
+ }