We do what aLiE suggested, but on a less frequent basis. We have a scheduled task on our WDM server that replaces the image we use on a weekly basis. Our screensaver is made up of a nice picture with our corporate values and logo written on them. One picture is equal to one value. One our PC’s we use the slide show screensaver to display all of them but on the Wyse units we cannot do that so we do this instead.
our units are configured to reboot at logoff, so every day a unit that is in use will eventually be rebooted and get the updated screensaver. But you are at the mercy of the users – unless you want to also go reboot the units yourself – but that will not make you too popular.
We use the jpeg format to try and keep the image file size small. But that being said I found I had to experiment with the resolution so it appeared properly. This is probably documented somewhere – I found 600 pixels wide worked well.