diff --git a/js/osticket.js b/js/osticket.js
index d55ea886c1bb501b532dc815704cf50396217f42..69839eb3b9dc4c6db51f01855673b5a45416ff07 100644
--- a/js/osticket.js
+++ b/js/osticket.js
@@ -131,7 +131,7 @@ showImagesInline = function(urls, thread_id) {
         ? '.thread-body img[data-cid]'
         : '.thread-body#thread-id-'+thread_id+' img[data-cid]';
     $(selector).each(function(i, el) {
-        var cid = $(el).data('cid'),
+        var cid = $(el).data('cid').toLowerCase(),
             info = urls[cid],
             e = $(el);
         if (info) {