ImageMagick and GD are two of the most popular graphic software libraries nowadays. They make the dynamic creation and editing of images and graphs on a site possible, so they need to be present on a server if you host your sites on it and you prefer to have something different from static images with fixed dimensions. If ImageMagick and GD are set up, you will be able to edit any image in a variety of ways - generate thumbnails, change the colors, flip it, blur it, and so forth. Naturally, these changes are feasible if the script app which you use on your website enables you to do such things. The two libraries can be used with numerous programming languages - PHP, Python, Perl, etc., and support over a hundred frequently used image formats which you will be able to work with - PNG, PSD, JPEG, TIFF, GIF and more.