Maybe a previous firmware updated added a Viera screen saver that senses inactivity? No way to turn it off in the eco menu or anything?
In the meantime, maybe try making a copy of your white slide but give it a different file name, then put just those two files on your USB drive and run a slideshow at the slowest setting. Maybe it will seemlessly toggle back and forth between the two slides.
In the meantime, maybe try making a copy of your white slide but give it a different file name, then put just those two files on your USB drive and run a slideshow at the slowest setting. Maybe it will seemlessly toggle back and forth between the two slides.