Originally Posted by Neesie

With most, you can right-click and choose 'copy image' or 'save image to' command. To repost, you'll need to save it to your computer, then upload from there.
Another way to save an image, is to take a screen shot of an image - keyboard commands Ctrl + Print Screen. This will take an image of your computer screen. Using an editing program, you can crop the image, to save just the photo.