Files having extension .BMP represent Bitmap Image files that are used to store bitmap digital images. These images are independent of graphics adapter and are also called device independent bitmap (DIB) file format. This independency serves the purpose of opening the file on multiple platforms such as Microsoft Windows and Mac. The BMP file format can store data as two-dimensional digital images in both monochrome as well as color format with various colour depths.
Files with .htm extension represent Hypertext Markup Language for creating web pages for display in web browsers such as Google Chrome, Internet Explorer, Firefox, and a number of others.
You can also convert BMP into many other file formats. Please see the complete list below.