A friend was sending me full sized photos, and I was trying to explain how to use Graphic Converter to scale, but don’t save, be sure to save as, on the desktop, then drag into mail, blah blah blah. Recipe for disaster heh.
Then I saw iPhoto has a Share via Mail function, which is simple, but pretty damned near has to be. It works well, does the scaling and even stores the scaled folders in /tmp
Just be sure to send the email before rebooting, or the scaled attachments will be deleted.