[Beery]

One thing I can tell you is that SH3 tends to use skewed images for a lot of the game screens. The game's loading screen is 1024 x 1024, and the game simply chops off the bottom and top to make it appear properly in the game. Other menu screens are 1024 x 512 and the game stretches them to fit.

Possibly stretching or compressing the image will work on this map image, although I can't really tell without seeing it. If it's 1024 x 1024 you may need to use the 'Image size' feature in Photoshop to distort it to 1024 x 768 (you can do this by unchecking the 'preserve image size ratio' check box). After you've finished editing it you'll be able to stretch it back to its original 1024 x 1024 size and save it.