Thanks for your reply. It is good to see esc will be added to unselect stuff.
I was wanting to force-save images with less than 256 colors in the GIF format. I believe this produces a smaller GIF color table (2-128 entries rather than the full 256). That said, the file size difference is minor compared to the size difference of 32-bit and 8-bit BMP files, so it isn't really as big an issue for me, and I know there are lots of batch GIF optimization utilities out there I can use if I do need this.
I remember Photoshop had a very nice "Perceptual" color reduction tool. I'm not sure what algorithm it used, but it produced very nice color reductions with minimal visual changes, at least to the human eye.
Thanks for your time and good luck!