Sure it's possible.
I've thrown together a little example here: http://hibbard.eu/blog/pages/iframe-color-picker/
I've used sstrudeau's jquery-dropper plugin to implement the eye-dropper.
I've then taken his basic demo, stuck the images etc within an iframe and tweaked the code a little.
If you have a look at the page source, you should be able to see what's going on.
If you have any questions, just let me know.
If it helps, I can also send you the files.