...If it concerns Images into your menu data folder, use GPI Browser and click on "Save all images in .tga" button.
.... If you have a lots of GPI files out of your main game and that you want to convert them in tga, use Slimtex: click on "Batch to tga" button, just select and slide all your GPI file from your folder window into Slimtex, then, convert. It's done! ;o)
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