XLSXMicrosoft Excel Open XML Spreadsheet
XLSX is well-known format for Microsoft Excel documents that was introduced by Microsoft with the release of Microsoft Office 2007. Based on structure organized according to the Open Packaging Conventions as outlined in Part 2 of the OOXML standard ECMA-376, the new format is a zip package that contains a number of XML files. The underlying structure and files can be examined by simply unzipping the .xlsx 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.