What Is BMP? Understanding the Bitmap Image Format

What Is BMP? The Bitmap Image Format Explained You got a .bmp file from somewhere — an old Windows program, a scanner, a legacy system — and now you need to do something with it. This article covers what the BMP format actually is, why it creates enormous files, and how to convert it into something usable. What Is a BMP File? BMP (Bitmap Image File) is a raster image format developed by Microsoft in the late 1980s for Windows and OS/2. It stores pixel data in a straightforward grid: every pixel's color value is written sequentially, row by row, with minimal processing. That simplicity was a feature in 1988. Programs could read and write BMP files without a decoder, and it worked across all Windows software. No compression needed, no encoding logic, just raw pixel data. The trade-off: BMP files are enormous. A format designed for simplicity carries a permanent size penalty that modern formats solve entirely. BMP is sometimes called DIB (Device-Independent Bitmap), which refers to the sa