The best idea would be to use .DDS files for HUDs, and have a copy of it in .TGA aswell (just in the same folder).
This is because when I tried to use a .TGA file on its own (without a .DDS in the folder), the preview game crashed.
Also, for the transparency, it would be easier to just make the HUD the right size, so that the canvas in your editing programis about the same size as the actual image.
Then, you have to fiddle around with X and Y positions, although I don't remember where! (Anyone know?)
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