The DIB (Device Independent Bitmap) is a raster image format which was introduced by Microsoft on the Windows 2.0 platform. The bitmap created for Windows 1.0 was very simple. It had a fixed color palette. This format was a Device Dependent Bitmap (DDB) and in contrast with DIB. So, as Windows 2.0 was being developed, support for a programmable color palette was added to Windows, and BMP, formed the DIB format.
A DIB file with its simplest and the most widely used structure holds 3 bytes of data; 8 bits for each red, green and blue channels. Other data representations like alpha channel and indexed color are also supported, but not commonly used and implemented.
Although there are several compression methods and algorithms available, the most common form of DIB format is uncompressed, resulting in large file sizes. This makes DIB image a bad choice for web photographs. It's a good idea to choose WebP for its compression with a fallback to JPEG for its better compatibility.
The DIB format is very similar to BMP format; the former has different and extra header information.