XLSBMicrosoft Excel Binary Spreadsheet File
XLSB file format specifies the Excel Binary File Format, which is a collection of records and structures that specify Excel workbook content. The content can include unstructured or semi-structured tables of numbers, text, or both numbers and text, formulas, external data connections, charts and images. Unlike XLSX (which is based on Open XML file format), the XLSB represents binary Excel workbook file.
BMPBitmap File Format
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.