Media Cache Saver от Lucky

Saves images and videos you see while browsing straight to your computer, without re-downloading them — it just grabs the copy your browser already fetched. Turn it on per-site with one click, set a folder name and a storage limit, and it quietly saves stuff in the background as you scroll. Has a filter to skip tiny icons/avatars so you don't end up with a folder full of junk. Everything stays local — nothing is sent anywhere.