wusage_screen_properties.gifto the top directory of your web server's web space. This file was provided with Wusage. If you cannot locate it, check the Wusage home page, or use any image you like. The important thing is that you place it in the top directory of your web space and give it the correct filename.
wusage_screen_properties.gif image is a 1x1 pixel transparent GIF. It has no visible effect on the web page in which it is installed to collect information.