There are many factors to consider when handling images — canvas size, file size, resolution, vector or raster, compressed or raw, etc. Careful handling is easiest in a GUI image editor such as Inkscape or GIMP. But sometimes, you just need to make a quick, straightforward change — say, converting an image to a different format or creating a thumbnail image from it. In those cases, ImageMagick is a great option.

Imagemagick's convert command-line (CLI) utility allows quick conversion from, say, png format to jpeg format. The documentation is good and the code is well-maintained, keeping up with evolving file format specifications. As with all CLI programs, ImageMagick is easily called from scripts.

The thumbnail images in the tedm.us gallery were created with ImageMagick. Whenever I upload a new image through the administrative web interface, the Django code handling the upload initiates a call to ImageMagick using the subprocess Python module.