Firefox have added a Screenshots options to their browser.
I have been using and love Fireshot Pro, but this addon from Firefox is free!
You can select any graphic element from a page for Firefox to extract and download for you, or you can choose an area with a drag across the screen. You can also upload to your personal cloud space which keeps the image for 14 days.
Unlike Fireshot Pro, there are no edit or other options, but for a quick and easy way to copy and use an image from a website or capture part or all the page, this is an easy and useful tool.