Yes, but power of 2 means: 1, 2, 4, 8, 16, 32, 64, 128, 256, etc. If it is a different size then GP4 works fine (DirectX 8 can also handle .png), but GP3 will show the images wrapped somehow, not what you want.
The internal size is hardcoded though. For example, in digital 2010, an image that was 222 pixels wide is a 256 pixel .tga, but the code uses the first 222 pixels only. In this mode I also assume sizes of edges for vertical alignment. Digital 2004 is easier to change.
René Smit, Independent Software Developer.
Download my GPx tools
here.