My order from smallest to largest is GIF, XCF, JPG, TIFF
GIF are typically small and very portable in size. They are widely used for web graphics.
XCF is an image file created by a freely distributed image editing program called GIMP. It saves layers, paths, channels, and paths when saved
JPEG – The most commonly used on the internet and very popular for digital cameras. It is used in both larger file sizes and smaller ones.
TIFF – Lossless images that allow very high quality and larger file sizes.