I see there are lots of suggestions for photo frame support (i.e., Downloading a JPG and having it automatically appear on an Android device as a rotating screensaver.)
What I wanted to add was that a button in "Actions" that said Dropbox and downloaded the eQSL to the user's Dropbox is all that's needed (from the user perspective.)
There are already programs such as
https://slideshow.digital/ that will sync a Dropbox to an Android device.
Something unique is that https://slideshow.digital/ is open to private labeling their software so that there could be a eQSL.cc "product."
https://slideshow.digital/branding/. I have nothing to do with this product -- just a user.
A bonus idea would be to see whether https://slideshow.digital/ has the capability to mark various files as "protected" so that your coolest QSLs are never deleted. The user could select how many cards they want to have in rotation and then when a new one is added, the oldest is deleted so the number stays the same. This could potentially all be done in the https://slideshow.digital/ product should they be so inclined to add this enhancement.
KB0US Mark Rosneck