I've tried using WP 3.7.3 and WP 3.9.1 and it is impossible to upload an image correctly. Some images are created, others aren't. It is like somthing is causing the upload process to take so long that it fails.
As soon I disabled the plugin I was able to upload photos.
Enable it, and you won't be able to upload photos that can be USED or selected. Images can be find at the Uploads folder but they just cant be used don't know why.
Needs an update!