Rotating forum avatars

A friend has asked me to help him with a rotating forum avatar - that's my description and not his!

On a particular forum, he wants to specify in his user profile his avatar as http://some_php_host/avatar.jpg and have that web host deliver one of about 5 avatars at random or simply have them rotated in a pseudo-random manner.

I've done a bit of Googling and I keep on getting explanations on how to rotate banner ads and the suchlike, none of which is really what he wants.

Bearing in mind that I'm pretty much a php novice, can anyone here suggest something ready-made that more or less just needs uploading and configuring, please?

In an ideal world, there would also be a simple avatar upload interface too, but that really is the icing on the cake!

Funny you should mention this. I am in the process of doing a simple avatar manager site that allows rotating avatars and such. That might not be up for a bit, though.

The one I have for my avatar is very simple; it just gets a list of files in a directory and randomly picks one to return. OK, well, it's a little more complicated than that, but either way the PHP for it is simple. I'll see about cleaning it up if you want it.

Oooh, yes please. That sounds exactly what I'm looking for. It perhaps also gives me an everso gentle introduction into php, which is long overdue!