Facebook groups...10 pts?

[snip_from_mars]

You would have to either remove any photo you have uploaded to their group or delete your comments. Those are the reasons why you would get those notifications in the first place.
Or you can also go into your settings and change the notifications for photos and groups etc. You can easily turn them on and off from there.
To do this just look for the "settings" link on the top of your Facebook page and click it. Then you should see a tabbed page with such tabs as "settings" and "networks" etc. Click on the one that says "notifications" and just scroll down till you come to the part about photos...groups should also be just under the photo section.