If you like to run custom desktop background on your system, you have probably accumulated quite the amount of images for that purpose over the years.
Switching between those wallpapers was quite difficult in Windows versions prior to Windows Vista, and you had to resort to third party software to automate the process.
Microsoft did integrate options to select multiple wallpapers in Windows 7, and the feature has been part of the operating system ever since.
Basically, if you want to select multiple wallpaper images, you select them all in the desktop background control panel. The only limitation here is that the images need to reside in the same folder for you to select them all for display.
Then it is just a matter of selecting the change interval and decide whether you want Windows to use the order of pictures, or shuffle them around for some randomness.
If you are not using Windows 7 or newer, or simply want better control over the wallpaper shuffling, then you need to use third-party software to do so.
Spews, which stands for S* Process Excluding Wallpaper Switcher (select any word that fits for the S, for instance Stupid or Super). It has been created by SKWire, one of Donation Coder's most active developers.
The program is fully portable, which means that you can run it right after you have extracted it to your operating system. It is compatible with all versions and editions of Windows from XP onwards, which means you should not run into any compatibility issues either.
The program interface is really easy to use. First thing you need to do is add at least one folder with images to the application. Just click on add path, select the folder, and decide whether you want to include all subfolders of it as well. Repeat the process until you have added all folders with wallpapers that you want the program to use.
You can then go ahead and use the configuration options below to customize when and how things are displayed on the screen.
Wallpaper options include changing the interval in which they are rotated, whether you want that to happen on system start, and how you want the program to handle images that do not fit right away.
There are also options to run the program with Windows and to start it minimized.
Another interesting option is the ability to prevent the changing of wallpapers when processes are running that you enter here. This may be useful if you do screen recordings for example.
The main thing that Spews has going for it is the ability to block the switching when select processes are running. While Spews needs to run in the background for the wallpaper switching to be enabled, its process is rather low on resources with its 5 Megabytes of RAM usage.
Still, some users may prefer a program that does only run when it is switching wallpapers, and not all the time. If you prefer that, you can use something like Wallpaper Shifter instead which only runs when images are switched.
And if you need some wallpapers, check out Reddit's Wallpaper Dump forum.