Open HEIC File

BMP and DIB Files

BMP and DIB file extensions are used by files in Bitmap image file format. BMP and DIB files store computer images in as an uncompressed or compressed bitmap. Bitmap files also support storing alpha channel information, color palettes and can be used to store images with different color depth (from 1-bit to 24-bit).

Since BMP is one of the oldest image file formats it is widely supported by various graphics applications from simple image editors like Microsoft Paint to complex products like Adobe Photoshop. All major operating systems including mobile ones support Bitmap File Format.

As of now BMP file format is used on just 0.2% of websites on the internet. Due to the lower compression percentage and lack of interlacing support bitmap file format is more suitable for operating system internal purposes rather than internet image storage and transfer. In-memory bitmaps in DIB format are still widely used by Windows Operating systems for internal image transfer (clipboard images are stores as DIB bitmaps). Operating systems and archiving software knows how to compress bitmap files efficiently which makes Bitmap File Format a simple and efficient file format for in-memory image storage.

To make image storage more effective for images with limited number of colors Bitmap File Format uses allows defining a color table with all colors used in the stored image listed prior to the image pixel information. Using color table and indexed colors considerably reduces size of the bitmap and allows for better compression.

RLE or Huffman algorithm is used to compress information in Bitmap Image Format. These algorithms provide great performance but often provide mediocre compression ratio. That’s why Bitmap Image Format is rarely used to transfer large number of images and JPG, GIF or PNG formats are preferred.

BMP and DIB files are transferred over e-mail or internet using following file multipurpose internet mail extensions (MIME) types: image/bmp, image/x-bmp. ICO and CUR file formats are based on the subset BMP file format.