thanks for the hint! At last I downloaded the component version as well, but unfortunately I can't get it to work (independent of the system). Looking in the developer tools of my chrome browser I found out that somehow the structure of the component is not implemented properly (see image #1 - #2 shows how it should normally look like). But unfortunately I have no idea what might be the reason for this...
I also did some further investigation of the extension version of the BackgroundScroll feature on different Apple devices - iPad Mini, Mac OS (using Safari 12.1.1) and of course again the iPhone (iPhone 6S using Safari 12.1). And I found out that obviously the images are there, but they are - why ever - on the iPhone as well as on the iPad Mini (not on the Mac OS) scaled up in an exorbitant way (see image iPhone). And even if I see a picture, if I scroll down it ends and then there is nothing (see 2nd image of the iPhone).(The Android image shows the correct appearance: I have 2 images of the same situation - one at daylight, the other one at nighttime; by scrolling you can swap between them)
So, any idea what might be going wrong on the iPhone?
I really like the user to be able to change from day to night by his own action and would only reluctantly abandon it...