diff --git a/photoswipe/photoswipe-tests.ts b/photoswipe/photoswipe-tests.ts
index 79125bd05f..ca136f3a2e 100644
--- a/photoswipe/photoswipe-tests.ts
+++ b/photoswipe/photoswipe-tests.ts
@@ -6,13 +6,11 @@ function test_defaultUI() {
             src: "path/to/image.jpg",
             w: 100,
             h: 200,
-            specialProperty: true
         },
         {
             src: "path/to/image2.jpg",
             w: 1000,
             h: 2000,
-            specialProperty: false
         }
     ];
 
diff --git a/photoswipe/photoswipe.d.ts b/photoswipe/photoswipe.d.ts
index b09fe75ddf..4916c2123f 100644
--- a/photoswipe/photoswipe.d.ts
+++ b/photoswipe/photoswipe.d.ts
@@ -268,6 +268,16 @@ declare module PhotoSwipe {
          */
         mainClass?: string;
 
+        /**
+         * Undocumented.
+         */
+        mainScrollEndFriction?: number;
+
+        /**
+         * Undocumented.
+         */
+        panEndFriction?: number;
+
         /**
          * Function that should return total number of items in gallery. Don't put very complex code here, function is executed very often.
          *