Photoshop(with topaz labs) and Photoscapes
You can get past original version of Photoshop for free on adobe webpage and get a month-trial topaz labs on its page, also free of cost.
Photoscapes is free and more user-friendly photo editing program than Photoshop.
Oh but for your info, photo-editing(at least how I do it) dosen't drastically change how the chars look. It's more like a makeup, not a plastic surgery. I hope my answer to be of your help:)