Windows: Ever find a great image but then forget which site it was on? Using CacheCopy, you can automatically rip images from your browser cache into a folder of your choice to keep a permanent copy.
You can tweak the utility to specify how many hours' worth of images to grab, and set size limits so you're not grabbing emoticons, avatars and other small image files.
The program is an alpha release so some features need work. I had to manually direct the program towards my Chrome cache when it couldn't find it automatically. Also keep in mind the program won't work on images viewed during private browsing sessions as that mode does not cache graphics.
If you need to routinely grab images, give this a try. You may also be interested in learning how to manually pull images from your browser cache.