Source: http://lifehacker.com/5594846/lightshot-is-a-lightweight-and-fast-screenshot-capture-tool
Windows standalone or Firefox/Chrome/IE: If you're looking for a snappy screenshot tool, LightShot is lightweight, fast, featured packed, and available as a stand alone application or a browser add-on.
LightShot is a lightweight screenshot tool available for Windows or as an add-on for Firefox, Chrome, and IE. You can capture screenshots in a variety of ways including uploading them to the internet via ImageShack, dumping the sreenshot to your clipboard, opening the screenshot for editing in Pixlr, or simply saving them to your computer as a JPG, PNG, or BMP. LightShot also supports hot keys for every major function—CTRL+E, for example, launches the online editor for your images while CTRL+D uploads it to ImageShack.
LightShot is a free tool and requires no registration. If you'd like to check out other screenshot tools make sure to take a peek at our previous Hive Five on the topic Five Best Screen Capture Tools. Have a favorite lightweight screen capture tool to share? Let's hear about it in the comments.