Embedding images inside a GitHub wiki (gollum) repository?

Question

The Github wikis are backed by a separate git repository then the main project repository.

This post by the Github team makes it sound like you should be able to link to

Answer 1

James' URL format did not work for me, perhaps it has been changed. I have used:

https://github.com/username/project/wiki/pathtoimage/image.extension

Where pathtoimage is optional.