Origin
BMP grew out of the Windows graphics model. A bitmap was a direct way to represent a rectangular grid of pixels, and device-independent bitmaps gave Windows software a common structure for moving raster images between files, memory, printers, and displays.
That directness explains BMP's survival. It is not elegant for the web and rarely efficient, but it is easy for old programs to read and write.
Technical characteristics
A BMP file usually contains headers followed by pixel data. Depending on the variant, it can store indexed color, grayscale-like palettes, or full-color pixels. Many BMP files are uncompressed, so file size grows quickly with width, height, and bit depth.
Because BMP is simple, it avoids some quality questions. There is no JPEG-style generation loss if the pixels are stored uncompressed. But simplicity does not mean small, portable, or web-optimized. Metadata, color management, alpha support, and compression behavior vary by variant and software.
Where it fits
Use BMP when a legacy Windows application explicitly requires it, when debugging raw pixel pipelines, or when you need a very simple raster container for local tooling. For normal sharing, archiving, or web use, PNG is usually a better lossless choice and JPEG/WebP/AVIF are better for photographs.
A practical rule: if you receive a BMP, convert a copy to PNG for lossless everyday use or to JPEG/WebP for photographic delivery.
Best uses
- Legacy Windows software
- Simple local raster tests
- Cases where an app specifically requests BMP
Use another format when
- Web pages and social sharing
- Large photo collections
- Workflows that need compact files