When using BMP images, it's BGR format. You can make Gamestudio write BMP images. When writing the color 64, 128, 255, which is sky blue in the RGB format, it's treated as a bright grayish-orange color in the BGR format. You can see this for yourself. Just use this RGB color and save a small 16x16 BMP image of all this color. In a hex edittor, you'd see it as FF 80 40 repeated 256 times after the 54-byte file header data. I don't know if this applies to other image formats (like JPG, PNG, GIF, or, more easily, TGA (easy when uncompressed - Gamestudio can write uncompressed TGA images)).