ImageMagick is such a cool and powerful tool to manipulate images, it’s a real shame if you don’t make use of it during your web design or photo album creation. From resizing, compositing and converting all types of file types, it’s list of usability cases is endless. It’s free and available for almost every operating system.
If you don’t have it on your system yet, here is the imagemagick download location. You might also have it in your repository, check your package manager as it might be as simple as calling “sudo apt-get install imagemagick” (on Ubuntu) or “sudo yum install imagemagick” (on Red Hat/CentOs).
Here is a small compilation of command-line tools (by no means a complete list). The list of available commands is actually sheer endless, you’ll be amazed by how powerful this application is.
convert image.gif -resize 128×128 resized_image.gif
convert image.gif -crop 240×360 cropped-image.gif (add’l params for crop location: 240×360+10+10)
convert image.gif -rotate 90 rotated-image.gif
convert image.gif -flop mirrored-image.gif
There are many more, actually way too many to list them all here. Have a look at the official ImageMagick usage page for a complete list of image manipulation actions.