Image upload doesn't set committer name correctly on commits

[durden]

We' setting the commit author to the image filename instead of the author when uploading images via the Github API. Luckily, this doesn't show up incorrect on github because github.com tracks commits by email, not username. However, when you clone the content repo locally you'll see image commits with usernames like f07b191d-39a8-40e2-b48c-f5580c9a4249.jpg even though the email is correct.