the "deleted" files are marked by the system and put in a special place in the hard disk, so do not feel bad.
another thing is when you format the disk, but that shouldn't happen often if you use a decent operative system (read no-Windows)
I know you are not supposed to throw away papers with Krishna's picture on it like incense packages and all that.
But what should one do with them then?
Also, what about digital pictures that one took with a camera and printed photographs that didn't come out all that good? One has to clear them camera memory card at some point. And what about the pictures one receives and sends in emails?