I'm trying to remove pictures from iPhone 4 but its not letting me?

I purchased a used iPhone 4 from someone and I'm trying to get of the pictures and photo albums he left on the phone but I can't seem to find a way yo delete them. Anyone know of a way to delete pictures from albums, and then the albums themselves?

Https://discussions.apple.com/thread/3777283?start=0&tstart=0