"It seems we are constantly striving to be better, faster, stronger, smarter. The good news is there's a new weapon in your arsenal against time. It's called SiteSucker, and it's something I will be keeping in my Applications folder for the next while, if not forever. Best of all, it's free.
Authored by one Rick Cransky from the U.S., SiteSucker works literally like a vacuum cleaner, picking up images, backgrounds, movies and stuff like that. It saves them to a folder your desktop (or specified location) on your Mac, so you can do whatever you want with them after. How does it work? SiteSucker uses WebKit to asynchronously download the files on your machine. It doesn't interfere with your browsing of the site either."