Manip

Manip = Short form of "Manipulation" 

Refers to an image that is created, usually via Photoshop (or some equivalent software), by manipulating a pre-existing picture into a new creation. May be quite an obvious alteration to the original image or look very realistic. May also be erotic in nature, in which case they are often marked "NSFW" to forewarn viewers to be careful about when and where they open them.