Index: wp-includes/template.php
===================================================================
--- wp-includes/template.php	(revision 21103)
+++ wp-includes/template.php	(working copy)
@@ -303,15 +303,17 @@
  */
 function get_attachment_template() {
 	global $posts;
-	$type = explode('/', $posts[0]->post_mime_type);
-	if ( $template = get_query_template($type[0]) )
+
+	$type = explode( '/', $posts[0]->post_mime_type );
+
+	if ( $template = get_query_template( "$type[0]_$type[1]" ) )
 		return $template;
-	elseif ( $template = get_query_template($type[1]) )
+	elseif ( $template = get_query_template( $type[1] ) )
 		return $template;
-	elseif ( $template = get_query_template("$type[0]_$type[1]") )
+	elseif ( $template = get_query_template( $type[0] ) )
 		return $template;
 	else
-		return get_query_template('attachment');
+		return get_query_template( 'attachment' );
 }
 
 /**