Picture files that aern't really there showing up?

I know I read this somewhere before, but I can't find the thread anywhere. I want to know why picture files that have been deleted off my hard drive still show up when I am trying to add a picture on dg. I recently deleted every file of pictures off my computer except one and I am still getting files that are from a year ago. They are not really on my computer because if I try to upload one it says error. I'd like to get rid of these empty files so I don't have to scroll through a bunch of files that aren't even there and adding pictures is easier. Thanks for any help. : )