All digital images fall into one of two main categories: raster or vector.
Photoshop is the most popular raster image editing application. Photos and paintings created in Photoshop are made up of pixels (short for picture element). A pixel is the smallest physical point in an image. Pixel-based images are called raster or bitmap. Raster images have a fixed resolution at which they look best. When scaled up, quality is lost and you may see pixels or jagged edges.
The image resolution is made up of pixels (measured in pixels per inch, ppi)
Images typically ...