You can only have 1 image at a time. We have a scheduled task on our WDM server that replaces the image we use on a weekly basis. Our PC’s use the slide show screensaver to display a series of images with our corporate values on 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.
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.