This site has HQ photos of a lot of celebs.
Here are Britney photoshoots; http://www.hqdiesel.net/gallery/thumbnails.php?album=1761
Here are some candids: http://www.hqdiesel.net/gallery/thu
OMG THANK YOU SO MUCH
I was getting her photos from a Britney site but they all had MQ pics
You saved me!
If you need a specific picture and know what it was done for, the photographer, or year, you can typically search google images and find similar links to HQ galleries.