Many thanks for the link. This is too technically difficult for me.
What I did see was this:
""
Of course, this means that you can replace the images in /etc/images and /usr/local/Kobo/slideshow by other images. Disappointingly, though, the interesting images (the "powered off" and "sleeping" logos) don't seem to be there and seem to be displayed in another way.""
This would seem to imply that what I want to do (replace the "powered off" and "sleeping" images by a photo) has not been explored yet. At least that is the interpretation of someone who has no technical background.
Should you come across a solution for this (but do-able by someone who can't read code!!
) I would be very interested!
Rojofo.