Photoshop is Adobe's photo editing, image creation and graphic design software.
The software provides many image editing features for raster (pixel-based) images as well as vector graphics.
It uses a layer-based editing system that enables image creation and altering with multiple overlays that support transparency.
Layers can also act as masks or filters, altering underlying colors. Shadows and other effects can be added to the layers. Photoshop actions include automation features to reduce the need for repetitive tasks. An option known as Photoshop CC (Creative Cloud) allows users to work on content from any computer.
Photoshop been the industry standard image manipulation program for so long that its name has become a verb: It is common parlance to say that an image has been “photoshopped” or even just “shopped."
Shopped, in this context, is synonymous with edited, manipulated or faked -- often regardless of the software actually used.
Photoshop is used by photographers, graphic designers, video game artists, advertising and meme designers.