[Hex08]

That's exactly what Aseprite (a pixel-art tool) does. I think it's great, I got it to build on Windows but eventually ended up buying it on Steam because it's so good.

[dgellow]

Wait, Aseprite is open source?! I didn't know that, it's an awesome program.

Edit: Sources available, but not open source license as far as I understand the EULA. https://github.com/aseprite/aseprite

[richrichardsson]

More fully explained here : https://dev.aseprite.org/2016/09/01/new-source-code-license/

The license and FAQ are somewhat confusing as to if you need to pay for a license even if you compile from source.