Clean Computer?

I thought I cleaned up my computer. I had put all the photographs I took on a disk, but iPhoto puts in back ups and although I didn't have too many photos to begin with there was a huge group of photos that I thought I deleted but didn't. There were 100+ backup photos in about three different files. Now if I had accidentally got rid of them I would never find them. But since I wanted them out they were taking up soooooo much space. It took me forever. I hope I didn't screw up my hard drive. I wish Macs had a defrag function.