The fileformat should not make a difference as far as texturing is concerned -- as far as I know, the image data is stored in video ram in uncompressed form.
That means that after starting the program and loading the textures, they are in neither JPG or BMP format, but raw image data.
You still have a choice though: using .JPG for your textures will make the image you have to distribute with your program smaller, but will typically also be of lower quality (compression artificacts) than BMP would.
That means that after starting the program and loading the textures, they are in neither JPG or BMP format, but raw image data.
You still have a choice though: using .JPG for your textures will make the image you have to distribute with your program smaller, but will typically also be of lower quality (compression artificacts) than BMP would.