Capture-Convert

thumbalizr

From the site:

With thumbalizr you can take screenshots of any webpage you want. Use it for your presentations, documentations, visualisations or your webpage.

Just enter the target-URL and press the "thumb it"-button. Wait a moment and a screenshot of the desired page will be taken. You can choose between a screenshot with a fixed height of the screen or the complete webpage.

That's it! Just click one of the resolution-links (320, 640, 800, 1024 or 1280 pixel width) to download your screenshot.

UnPlug Firefox Extension

From the site:

UnPlug is an extension which lets you save video and audio which is embedded on a webpage - it's a video download tool.

UnPlug scans web pages and tells you where media players are getting their data from, and displays it as a simple hyperlink: in most cases, you can then follow the simple download link to save the media file.

UnPlug works for lots of sites including youtube.com, ifilm.com, current.tv, revver.com, peekvid.com, video.google.com, mobuzztv.com and lots, lots more.

Unlike many other extensions, UnPlug scans the page, and if it doesn't know there the data comes from it can guess - correctly most of the time.

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