diff --git a/web/viewer.js b/web/viewer.js
index fdf8f9fd4..838b3dfb9 100644
--- a/web/viewer.js
+++ b/web/viewer.js
@@ -1036,8 +1036,8 @@ var ThumbnailView = function thumbnailView(container, pdfPage, id) {
   };
 
   var viewport = pdfPage.getViewport(1);
-  var pageWidth = viewport.width;
-  var pageHeight = viewport.height;
+  var pageWidth = this.width = viewport.width;
+  var pageHeight = this.height = viewport.height;
   var pageRatio = pageWidth / pageHeight;
   this.id = id;