There are a number of image file formats. Each file format has a set of attributes that make it suitable for different uses. Each have different features such as file size and quality. Typically, the jpeg format is used as it provides a good balance of quality and file size. This guide will explain more about jpeg and other key file formats, as well as when you should use each one.
The most popular file formats are JPEG, GIF and PNG.
The jpeg is probably the most widely used image file format for web use. It is a compressed file format which means that you reduce file size in exchange for ultimate quality. JPEGs are used for photorealistic images and most commonly seen on web sites and used in applications such as Microsoft Word. JPEG files are usually named with the .jpg extension.
The above photo is a jpeg file.
GIF and PNG
GIF and PNG are used for images such as graphics, as opposed to photos. Nearly all logos that you see on the web will be in GIF or PNG file format. PNG is slowly replacing GIF as the file format of choice for vector images. PNG has a number of advantages over GIF such as the ability to use transparency. The ability to use transparency is useful when you want to overlay your image on an existing background, hence why it is popular for logos.
(An example of a PNG file is the graphic at the top of this section).