iMagine Photo is an 'application' whose sole purpose is to provide an Applescript interface for manipulating photos. It supports crop, rotate, color manipulation, border, text, exif writing and more. It's a great tool for adding into your new automator actions or applescripts.
I remember seeing this about a year ago, seeing the price, weighed against my need for such a tool, and moved along. I recently came back to check it out, and as of January 2005, it's now free! It has a lot of functinality, example scripts, and automator actions. Check it out.