The format has a TIFF-image structure. It is generated by Canon cameras. The CR2 photo is stored in an uncompressed form and allows you to edit such settings as white balance, exposure, and other settings for photos that were already taken. It is the successor format to CRW, which was used in previous generation Canon SLR cameras.
This format was created by Nokia for use in its proprietary phones. A bitmap image was used to transfer image files between devices over a wireless connection. It was mainly used when exchanging multimedia text messages that support inserting pictures.