No tip's here, but a real good TIP for those that like to screw with images with the DO command-line options.
Take a look at Image Magick !
You can do pretty much every well known image edition tool can, but from the command line, batch-processing, etc....
For those that wan't to use DO using Image Magick for mass-fiddling with an image collection, it's well worth to take a look at ! 