What is Photo manipulation?

Photo manipulation 

Photo manipulation  involves transformating or altering a photograph using different  tricks  and techniques to achieve expoected results.  Some image  manipulations are considered skilful artwork while others are frowned upon as unethical practices, specially when used to deceive the public. Other examples include being used for political works, or to make a product or person look better, or simply for entertainment purposes or harmless pranks or vulgarity.

Depending on the application and intent, some photo manipulations are considered  an art form because it involves the creation of unique& different  images and in some instances, signature expressions of art by photographic artists. Other examples of photo manipulation include retouching photographs using ink or paint,  airbrush, Double exposoure, piecing photos or negatives together in the darkroom, scratching  instant films, or through the use of software-based manipulation tools applied to digital images.