GNU/Linux Desktop Survival Guide
by Graham Williams
20190629 ImageMagick is a command line tool for transforming images. By combining digital image processing operations as a series of commands it provides a powerful ability to build image processing pipelines which can then be easily repeated. In contrast, graphical interfaces can sometimes become a burden, often requiring fiddly and manual interactions that do not have the precision and repeatability offered by ImageMagick.
ImageMagick provides the following commands:
Common operations include resize, blur, crop, despeckle, dither, draw on, flip, join, re-sample, and much more.
The basic command line will look something like the following which takes an input image file, resizes it to 25% of the original size, converts black to white, and writes the resulting image to the output file:
$ convert input.jpg -resize 25% -fill white -opaque black output.jpg
ImageMagick Tricks, by Sohail Salehi, 230 pages published by PACKT Publishing, 2006, ISBN 1904811868, available from http://www.packtpub.com/imagemagick/book, is a useful guide to using ImageMagick. It provides a tutorial like presentation illustrating many trick and tips.