There are probably all sorts of great wallpaper monitoring programs out there, but my favourite is Wallpaper Master Pro. I've been using the freeware version for a while, but finally decided to get the paid version, since I was quite happy with the functionality of it.
It can change the background every day at a specified time, change it at various other user-defined intervals, or whenever you start your computer. You can pick the directories you'd like to use, different people using the same PC can have their own configurations, it's quite neat.
But what I really love about it is that you can set it with one overall display setting for all your pictures, or so that different wallpapers are displayed in the ways that best suits them. You can also give each of your pictures ratings and set the program to display randomly with a bias towards the pictures you've rated more highly.
So much for the pitch. Why I really posted about the program is because while going through my various backgrounds, I realised that I had quite a few that had various friends in them. Not actually enough for my liking, but then I hadn't ever consciously went "I must add friends to my wallpapers", I just occasionally saw a picture of one of them and went "I'm adding that to my lists."
Some aren't the best pictures, but the reason I grabbed them was that I think the person in the shot rocks, and when they come up on my background for a couple of days, even if I'm going througha rough patch, it delights me to have them there and they never cease to bring a smile to my face.
So, below the cut, I present a selection of the pictures of people that I occasionally have as wallpaper backgrounds.
This is my current background. God I love my wife :)
For my mum's 70th birthday we took her to Arthur's Seat, a place she loves.
I am the Angel of the Lord... Arse-Kicking Division!
Dingo, I miss him so much.
Kal (short for Kaled Mutant) practising cute.
This man rocks!
As does this one!
One of my oldest friends.
Yup, gunna have to take more photos of my friends... And maybe scan a few old ones, too.