I remember seeing this somewhere but I can't remember where.

So if someone know about it help would be appreciated.

Not sure if you want browser extension (which browser?) or not. I don't know any browser extensions but I've used these two tools to download pics:

t621 looks nice, and works well for small number of pics. But you need to divide search and restart application a lot when dowloading over 200 pics.
E621 Massdownloader + tool look less nice (you have to modify file to change tags), names files with post no instead of md5, and doesn't seem to support multi tag searches, but it downloads all pics without trouble.