Great utility to take a screenshot of your current window, the entire page or just a section. This is available for Firefox and it works great. Created by Andy M.
Install as usual, then after installation you'll have a new icon on the bottom right hand corner of your Firefox browser. From there, you can choose to do a screen cap of just a section, or the entire site, or just certain viewable space on the web page.
In the settings of the addon you can pick other preferences like taking screenshots in jpg instead of png and whether you want the timestamp as part of the file name.
Simple, useful and very straight forward. I often use this instead of Skitch because it allows me to save a full website into an image with JPG or PNG option. This is very handy when I have to show the full view of a webpage to a client. I often use this also for initial consultations with a client in order to annotate changes that need to be made to their website. In the case that we're doing a critique or consultation, I take a full screenshot with screengrab, then I open the image with Skitch to annotate.
Go and get Screengrab for Firefox right here.