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 XLSM extension is a type of Spreasheet files that support Macros. From application point of view, a Macro is set of instructions that are used for automating processes. A macro is used to record the steps that are performed repeatedly and facilitates performing the actions by running the macro again. Macros are programmed with Microsoft's Visual Basic for Applications (VBA) from within the Excel Workbook using the Visual Basic Editor and can be run/debug directly from there.
You can also convert BMP into many other file formats. Please see the complete list below.