ImageMagick is one of the best tools to have, especially if you blog. It lets you manipulate images (resize, convert, …) in batch from command line.
On Mac OS X it is available as part of Mac Ports. Simplest way to install Image-Magick is to install Mac Ports using installers for respective version of Mac OS X. Installer will take care of adding directories to various relevant path environment variables.
Once installed open terminal and fire these commands:
sudo port selfupdate
port search ImageMagick
sudo port install ImageMagick @6.8.5-5
It will figure out the dependencies and install the tools appropriately in /opt/local directory.
- Image-Magick Page (imagemagick.org)
- A Bash script to force Image Magick to use zero-indexing when it converts GIF to JPG (penguinpetes.com)