Can i use Gimp and/or Gimp files (.gmp i believe) in Unity?

I was wondering if i could use Gimp instead of Photoshop or another paid program.

 

I'm sure you can use GIMP for your images with no problem. The only caveat I see is that I don't think Unity can import the gmp(if that is indeed what it is, not sure since I don't use GIMP) files directly. You can export to PNG, which supports everything you should need though, including the alpha channel, and no lossy compression. If you can't(or don't want to) buy Photoshop, GIMP works great, and this little bitty detail of having to save the image to PNG instead of the native format is totally worth it.

 

Gimp is using .xcf file format, and you can use Gimp in your project especially when you are using it with Krita they can be alternative to Photoshop