GitHub

SiteCapture is free and open source website screen capturing application. Anyone who needs to create a bitmap image of a website will find SiteCapture useful, however, I developed it with web developers, bloggers and online marketers in mind. Each URL captured is saved with the browser and image dimensions to easily recapture the image with a single click.

Compared to web-based services offering the same thing you’ll find SiteCapture allows you to choose any image size you want. Plus its much faster as you dont have to wait for a queue of requests to finish before you get your image.