Websnap is a firefox extension which will screenshot the entire page of a website, user can download the image in png, jpeg and gif.
Go to our firefox add on page at here, just click "Add to firefox" and the installation will begun.
After the installation, you will see the extension in your firefox toolbar.
And voila! The installation is complete!
To start the screenshot, click the extension icon in your toolbar.
At the new page, you could preview your screenshot and choose to download in whatever format.
Please feel free to submit an isue or a pull request. To develop, you will need a firefox browser and a code editor.