This changed from RGBA in
https://github.com/brendan-duncan/image/commit/f3d07a74d17d0004d88fc1043042df9111eb3b6f

Also added a test for this regression.

Issue: https://github.com/brendan-duncan/image/issues/92
Test: fx run-host-tests sl4f_client_tests
      end-to-end test
Change-Id: If8c82f9d5479d16e7c41845eb001d6ac8068ea27