you can donwload a free wallpaper script which has seo and its open source which means you can customize for your website and has search engine friendly links included with php mysql apache linux or windows does not require imagemagik 
if you are looking for a free wallpaper script. we recommend a wallpaper script with LAMP - that is Linux Apache MySQl PHP and important part of any website is to have good SEO, wallpaperscritp.org provides that. wallpaperama started with OSWallpaper - Open Source Wallpaper Script is the best because you can customize however you want it.
i put it on www.wallpaperscript.org