Images are an important part of a web site. And there are so many formats to save your images in that it can be quite confusing as to which format to use.
GIF (Graphic Interchange Format) has been the web’s default image for many years. This is traditionally used for images that are flat colors in nature and rather simple. GIF is best used on logos, buttons, bars, backgrounds, and other simple graphics.
JPEG (Joint Photographic Experts Group) is the standard format for photos that are used on the internet. Use this format for all of your photos, small or large. There are 16.7 million colors available with JPEG and a good compression rate as well.