A raster graphics editor (also called bitmap graphics editor) is a computer program that allows users to create and edit images interactively on the computer screen and save them in one of many raster graphics file formats (also known as bitmap images) such as JPEG, PNG, and GIF.
Each element is created and manipulated numerically; essentially using Cartesian coordinates for the placement of key points, and then a mathematical algorithm to connect the dots and define the colors.
A raster image is made up of rows and columns of dots, called pixels,[1][2] and is generally more photo-realistic.
Vector editors tend to be better suited for graphic design, page layout, typography, logos, sharp-edged artistic illustrations, e.g., cartoons, clip art, complex geometric patterns, technical illustrations, diagramming and flowcharting.
Advanced raster editors, like GIMP and Adobe Photoshop, use vector methods (mathematics) for general layout and elements such as text, but are equipped to deal with raster images down to the pixel and often have special capabilities in doing so, such as brightness/contrast, and even adding "lighting" to a raster image or photograph.