Free tool to edit .raw files?

[watermelon]

Are there any free tools available to edit .raw files exported by the Supcom map editor? I'm following the tutorial on the FAF wiki. It suggests using Photoshop or Paintshop Pro but they are not free. Tried Paint.net (with a plugin), and Gimp, but both do not handle the map editors .raw files.

[Tokyto]

I tried a few more, but only photoshop worked for me, so i guess you need to 'buy' it.