Bit MaP file - also known as a "bump" file, it is a Windows and OS/2 bitmapped graphics file format - it is the Windows native bitmap format, and every Windows application has access to the BMP software routines in Windows that support it. BMP files provide formats for 2, 16, 256 or 16 million colors (1-bit, 4-bit, 8-bit and 24-bit colour). BMP files use the .BMP or .DIB extensions (DIB stands for Device-Independent Bitmap)