R1:377a29644ffd

Display shield for generated binary files

Test Plan:
Displayed diff with generated images.

Should hide [[ https://secure.phabricator.com/D3579?vs=on&id=7076&whitespace=show-all#bfb5f5e5 | webroot/rsrc/image/autosprite.png ]] after deploy.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D3585