One of the most basic solutions to fixing a photo-copy and paste. Marquee, Lasso Selection Tools: Photoshop, GIMP, Paint.NET
Simply sample (and resample) and paint over your unwanted image areas to improve your photo. GIMP and Paint.NET work the same way, except you have to use the Ctrl key to sample your image. In Photoshop, hold down Alt to select a sample area, then paint it over your damaged areas with your left mouse buttons.
