(very resumed description)
Basic features:
-Customize file(s) and/or recursive folder(s) as source data
-Can excluded folders and files
-Change when windows or the program starts or every x hours/minutes
-Random o sequential image selection
-Start with Windows
**UNIQUE** Features:
-Changes the logon windows (win 7 only) to match the main desktop wallpaper.
-Smart multi-monitor support:
-Auto change when a display is plugged or unplugged or it is moved in the display array.
...
Changes wallpapers. Written in .NET (C#). To use it you just need to specify a folder where your wallpapers is stored. To add a new wallpaper you just need to copy file in the wallpapers folder. All subfilders will be seen as wallpaper categories.