ImageMagick and GD are two of the most widespread graphic software libraries nowadays. They make the dynamic creation and editing of images and graphs on a site possible, so they should be set up on a server if you host your internet sites on it and you would like to have something different from static images with fixed dimensions. If ImageMagick and GD are installed, you will be able to edit any image in many ways - create thumbnails, change the colors, flip it, blur it, and so forth. Needless to say, these adjustments are doable if the script application which you employ on your internet site enables you to do such things. The 2 libraries can easily be used with many programming languages - PHP, Python, Perl, and so forth., and support over 100 popular image formats which you will be able to work with - PNG, PSD, JPEG, TIFF, GIF and others.