Merge pull request #12510 from edx/douglashall/WL-450/fixed_timeout_issue

WL-450 Fix for issue with canceling changes to image upload fields

cms/static/js/views/settings/main.js

@@ -75,6 +75,9 @@ var DetailsView = ValidatingView.extend({
     },
 
     render: function() {
+        // Clear any image preview timeouts set in this.updateImagePreview
+        clearTimeout(this.imageTimer);
+
         DateUtils.setupDatePicker('start_date', this);
         DateUtils.setupDatePicker('end_date', this);
         DateUtils.setupDatePicker('enrollment_start', this);