That's what I thought at first, because it looks like it's peeling off at one corner. But there's actually no protective film on it (which is great from an environmental point of view!).
The favourable offer was from us, unfortunately we currently have no delivery date, so an available offer from a third party dealer is now being offered. However, this is considerably more expensive.
PDF is unknown to me, because you select the images from the mobile phone gallery via the Frameo app.
Regarding the image sequence: basically, the settings for the sequence, duration, deleting images, etc. can only be made on the frame. From a distance or via the app, you can only add pictures. If you want to delete some, then only AM frame. The same applies to the sequence. You can't "stop" it, but you can set it so that a picture is displayed for up to 24 hours at a time. Or you can delete all but one picture. Then you will only ever see the same thing. (Duration can be set between 10s-24h).
You can also set the standby mode, then you never have to switch off the frame, but it starts and switches itself off.
Fortunately, the settings on the frame are relatively simple.
I hope this answer helps. :-)