Bright, xdw is a proprietary image format used by Fuji Xerox DocuCentre scanners and copiers; may include both images and text, as well as links to Web pages or other documents. As far as I know, the only free Windows program that will open these files is a free app called File Viewer Lite for Windows and can be downloaded fro free from http://www.fileinfo.com/software/windows_file_viewer (latest version available is Version 1.1.1 - Released May 30, 2014).

There is also another program called FileViewPro which will open XDW files (as well as many other proprietary formats) available from http://www.fileviewpro.com/en/file-extension-xdw but you have to pay for this one and I don't know how much it costs.

However, even if you were to DL the free File Viewer Lite, it will let you open these files but if you wanted to email them to others there's not much point unless they also go to the trouble of downloading the same program. I just can't imagine why your friend wouldn't have used a freely portable format like JPG or PNG or BMP, or indeed just about anything else that can be opened by 99% of all available file viewers.

Your best 2 options here are to either buy an inexpensive scanner and do them yourself, or ask your friend to rescan them to JPG format (and keep your fingers crossed and hope that's what you'll actually receive next time). Sorry I couldn't be any more helpful than the above.