I am using GitHub Pages, Jekyll, and Prose to manage a Website. Everything works fine, besides I cannot find a way to upload images. The Prose image uploader is not working
If you keep your images in the Jeykll repo, they're uploaded and hosted. Just find them on GitHub in your repo, and pass the src of your img in your HTML the raw value.
Example: Image in my repo: https://github.com/kevinSuttle/kevinsuttle.github.io/blob/master/images/19698565-media_httpfarm5static_jhkva.jpg
Raw: https://raw.github.com/kevinSuttle/kevinsuttle.github.io/master/images/19698565-media_httpfarm5static_jhkva.jpg
It took me awhile to wrap my head around it also.