I'm curious if anyone has ever seen a script for this... I'm not very good at the scripting stuff, so hopefully it's already been done.
I have a lot of square/rectangle images. I need the images to be circle, and cut the remaining parts out and replace with an alpha channel. What I do manually, is create a perfect circle starting in the center and make it's height/width = the smallest dimension of the rectangle. I cut that circle, and paste into a new image with dimensions the next largest factor of 2 (the software for displaying them handles image with factors of 2 more gracefully) and an alpha channel.