A bitmap is a digital image composed of a grid of pixels, where each pixel is assigned a specific value representing its colour or brightness. The value can range from 1 bit per pixel (black and white) to as high as 24 or 32 bits per pixel, allowing for millions of colours and detailed tonal variations. Bitmaps are widely used in digital photography, computer graphics, and image editing, as they provide a precise, pixel-by-pixel representation of an image. Understanding bitmaps helps photographers and designers manage image resolution, file size, and quality for both screen display and printing.