O'Reilly Network: Living Linux: Transforming ImagesJul 15, 2000, 13:41 (0 Talkback[s])
(Other stories by Michael Stutz)
"There are many tools for Linux which can be used to transform or manipulate images in particular ways. One of the most versatile of these is the ImageMagick suite of imaging tools (available in the Debian imagemagick package...)."
"One of these ImageMagick tools, mogrify, is particularly useful for performing fast command-line image transforms -- use it to scale the size of images, rotate images, and reduce colors in an image. It always takes the name of the file to work on as an argument, and it writes its changes to that file. Use a hyphen, -, to specify the standard input, in which case it writes its output to the standard output."
"Let's take the sample image at the right and put it through the works. What can we do to it from the command line?"