Regarding notes: holding the tap too long I meant ...
Regarding format: I ruled out EPUB bc Amazon states it does not support e-ink-readers:
https://kdp.amazon.com/en_US/help/topic/G200634390
Aspect ratio of the picture: When I wrote that the ratio of the picture is wrong (after exporting and looking at it in Calibre) then I meant exactly that. I was not talking about how it did not fit the screen on all 4 sides. I know that both is not possible.
Any thoughts on that? Therefore I thought it has to be MOBI.
In light of all your input (thank you for that) I only have the following goals now: :-)
-maximum compatibility
-keeping ratio of pictures
-no additional margins (if there are margins bc of the device - so be it - although I have to say I still quite did not understand that ... cause any device that can show a pic can show it maximized to either (!) top and bottom or left and right) - or what am I missing? I am aware it cannot be screen filling on every device and keep the pic ratio at the same time)
I know a little about HTML, but def. not up to the point where it had to be for this. It wouldnt be only HTML but also I would have to know how each device treats certain things, wouldnt I?
So if coding is not an option, the next best is Word?
THX!