[DustyPorViva]

If you save it as JPEG or GIF in mostly anything, you'll probably end up screwing up your pixelart. JPEG is a compression format, it's meant to compress the image, which of course means lost data(image quality). With photos this is fine, but with pixel art that means loss of the fine pixel detail, which is bad, and also terrible artifacts where colors touch.

GIF can sometimes have color compression, and more often than not saving with GIF will screw up your colors somewhere along the line. I'd avoid it if you can.

Just stick with PNG.