Even if your pictures have been deleted from your hard drive, they will still exist untill a file is written over them, the only thing that is really deleted when a file is thrown away is its 'header' in your hard drives directory.
Think of it like this:
if you had a cassette tape of last weeks Top 40 chart,
and you wanted to record next weeks Top 40 chart over the top of this,
you would not have to blank the tape first, all you would have to do is peel the sticker off that says 'marsbtchsx's Top 40' put a new one on that says 'blank' and you are ready to go
........but crucially untill you hit 'record' the old Top 40 is still there.
So unless they have been written over, your deleted photos are still on your hard drive just not listed in your directory, to retrieve them try software like Norton Utilities which will rescue trashed files.
Obviously the more recent the deleting, the better the success rate, as less of the hard drive would have been written over by new files.
Ty