Summary: Builds out some images to use to identify repositories. Fixes T12825.
Test Plan:
Try setting custom, built in, and null images.
{F4998175}
{F4998192}
Reviewers: epriestley
Reviewed By: epriestley
Subscribers: Korvin
Maniphest Tasks: T12825
Differential Revision: https://secure.phabricator.com/D18116
