Multi-monitor Background Wallpaper
The Multi-monitor Background Wallpaper feature lets you overcome Windows inherent limitations for desktop background picture in a multiple display environment. By default, Windows clones its "Desktop" settings from the "Display Properties" dialog onto each monitor identically, i.e. displays the same background color and picture on all monitors without distinguishing them or considering their relative layout. So, even if you specify the picture large enough to cover the entire composite desktop - you will nevertheless see only the left-top part of that picture on each monitor. Also, there's no possibility to configure separate background settings for different displays.
Multi-monitor Background Wallpaper brings on the missing features when customizing the multi-monitor desktop background: you can either stretch a single background picture over the entire composite desktop or specify individual background pictures on each display forming the desktop. In addition, you can turn on the advanced slideshow mode that will flip pictures from various sources - either local image files and folders with image files or online image search service Flickr - on the background.
Hint Stretching a single picture better suits for nearly placed monitors aligned horizontally or vertically, inspiring the continuality and uniformness of all available screen space, which can significantly improve the overall look-and-feel of your desktop. Specifying individual settings for different monitors is recommended when you use each monitor for a separate purpose: different backgrounds will help you to instantly distinguish such monitors visually.