fix image viewer

apps/files_imageviewer/js/lightbox.js

@@ -18,7 +18,7 @@ $(document).ready(function() {
 });
 
 function viewImage(dir, file) {
-	if(file.indexOf('.psd')){//can't view those
+	if(file.indexOf('.psd')>0){//can't view those
 		return;
 	}
 	var location=OC.filePath('files','ajax','download.php')+'?files='+file+'&dir='+dir;