Could not upload and process my avatar.

Hello. I just installed multisite avatar, went to upload my avatar to test, and got a processing error.

I have tried a few images, big and small. I upload ok,. Then crop size, but never get past this - instead I get this error:

"Image could not be processed. Please go back and try again."

I go back once and get "Document Expired" page, then again to get back to "Your Avatar".

Is there something I can do to repair for my users?