Linux and Unix support many applications and tools for working with images and video files. Most Linux distributions include the imageMagick suite with the convert application for manipulating images. The full-function video editing applications such as kdenlive and openshot are built on top of the ffmpeg and mencoder command line applications.
The convert application has hundreds of options. We'll just use the one that extracts a portion of an image.
ffmpeg and mencoder have enough options and features to fill a book all by themselves. We'll just look at a couple simple uses.
This section has some recipes for manipulating still images and videos.