When you upload a thumbnail from ur HD, its not checked for dimentions, its simply posted.
Also, when you use a URL to upload an image, it doesn't auto create a thumbnail (it does when u upload). When u try to do it manually through the panel, 4images doesn't find the image without a thumbnail. SO bascially u gotta copy it to ur HD and then upload.
Thats the only bugs I found! The rest works great!