There are many different file formats because there are many different uses for images. There are also many ways to display images. Each file format may have an advantage that makes it more desirable for a certain project. It may also have a disadvantage that makes it less desirable for a project. For example, the JPEG file format is good for raster images that will be used on a screen and it is great for transferring over the web based on its small size. On the other hand, the JPEG file format compresses the image so it loses some of the quality, and each time it is saved the quality gets worse. For this reason, it is good to decide what the artwork will be used for and if the advantages outweigh the disadvantage. You then decide which other file format will be better.