I'm trying to upload artwork for this release: http://musicbrainz.org/release/9d3627de-db21-4b56-8215-38c6b7ecdbd2

The artwork is for a bonus CD in a three-disc limited edition DVD set. When I'm trying to upload an image of the DVD, I get an error.
This is what the error looks like: http://i.imgur.com/pZ7Zyx6.png
I get this error on both Safari and Chrome.

This is the image that I was trying to upload: http://i.imgur.com/PL0ltZQ.jpg (via http://dvdaholic.me.uk/phpdvdprofiler/images/013131161090f.jpg)