With the latest internal build we have addressed an issue which is workaround in the sample project my colleague has send you. This workaround is causing the issue you have observed, however as you are using the latest internal build it is no longer required and you should modify the Upload action method to return an instance of ImageBrowserEntry instead of an anonymous object:
path, HttpPostedFileBase file)
var files =
var parentFolder = files.GetFolderByPath(path);
Name = Path.GetFileName(file.FileName)
"File Not Found"
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