diff --git a/src/Site/BlockLayout/SmartGallery.php b/src/Site/BlockLayout/SmartGallery.php
index 61d47b7..9604898 100644
--- a/src/Site/BlockLayout/SmartGallery.php
+++ b/src/Site/BlockLayout/SmartGallery.php
@@ -91,11 +91,13 @@ class SmartGallery extends AbstractBlockLayout
 				$mediaType = $media->mediaType();
 				$mediaRenderer = $media->renderer();
 				if (strpos($mediaType, 'image/') !== false) {
-          $new_url = $media->originalUrl();
-          // original files size may be very large. /large/<name>.jpg is smaller
-          $new_url = substr_replace($new_url, 'jpg', strrpos($new_url, '.') +1);
-          $new_url = str_replace("original", "large", $new_url);
-					array_push($images, ["media_url" => $new_url,
+          $thumbs = $media->thumbnailUrls();
+          if (isset($thumbs['large'])) {
+            $media_url = $thumbs['large'];
+          } else {
+            $media_url = $media->originalUrl();
+          }
+					array_push($images, ["media_url" => $media_url,
                                "item_url" => $attachment->item()->url(),
                                "image_title" => $media->title(),
                                "img_id" => 'gi_' . $gallery_id . '_' . $img_id,