The main draw of photoshop, and it's free competitors such as gimp and paint.net (
www.getpaint.net) is that you can use layers. Old style photo editing was cumbersome due to the fact that if you messed something up, the whole image wasmessed up and you would basically have to start over.
Now that pretty much everyone does layers now, there are a ton of other useful tools.
You can't beat photoshop in my opinion, especially if you have the eye candy add-ons. Paint.net is free though.
I am unsure of what you mean by ghost...