We forgot to change the line rendering the image in commits 3574bf867c
and 810bdae37a, and so the custom image was being ignored.
Note that, in the test, we're stubbing a constant instead of adding a
new image. The main reason is that, if we add a new image, forks would
have to change the image when they change the `VALID_IMAGES` constant;
otherwise the tests would fail.
00ea1bf719