*EDIT*
Alright, I've added a new .wad to GameStudio, and am up to the point of adding a texture to that .wad. Now, when I try to add my textue that I saved in Paint, GameStudio says it is a bad texture size of 800x327. So, like the manual, and you have stated, this is because the texture is not set to a power of 2.
I downloaded the GIMP program online, and uploaded the texture to that. All I am trying to do now is figure out how to resize my texture in that program so that it will be in the power of 2. I was hoping you could tell me how to do that, and anything else I need to do in GIMP to upload the new texture to GameStudio. And I really appreciate the help

-Kravenwolf