I have a wallpaper site. It allows users to upload wallpapers, which are then resize or cropped into normal and widescreen formats. As the number of wallpapers is increasing it is getting difficult for me to keep track of all wallpapers already present in database and avoid duplicates. Is there anyway I can avoid duplicates automatically? The site is hosted on a IIS server and is scripted in PHP with mySQL backend. http://www.cybergeeks.co.in/hd_wallpapers.aspx (.aspx is for url rewriting only and points to dynamic php page)