I'm using Cura Thumbnails using a plugin in Cura 5.5. Also, I use the Marlin-based mriscoc firmware on a Creality Ender 3 V2 with OctoPrint using OctoPi on a Raspberry Pi 4.
The firmware supposedly supports Thumbnail's preview when printed from an SD card, although I never tried. I can also view the Thumbnail in the OctoPrint UI. I print only using USB, controlled by OctoPrint on my Raspberry Pi.
Is it possible to send the Thumbnail to the printer LCD when a print is started from OctoPrint? In a similar way to how I have to add 'Show Progress on printer LCD' using a Cura plugin to follow the progress on the printer LCD when OctoPrint controls it.