Batch-Jpeger resaves a copy of images in a folder to smaller JPEG files, suitable for emailing.
This will work on any debian-based 64 bit system for Linux, and anything running OSX 10.6 or later for Mac.
Be sure to choose either the 32bit version if you are running OSX 10.6 or earlier, or the 64bit version if you are running OSX 10.7 or newer.
If you have any suggestions, please get in touch via email. Many thanks.