Ok, so by your reaction, I assume the answer is: No :)
And no, my Image files mostly don't contain coordinates. So I enter them when uploading.
1) This image :
https://www.360cities.net/image/sundown-at-oberfeld-darmstadt
I fixed this image in the meantime.
I had copied the coordinates from google map. I can not give you the "exact" data ein entered for that, but approximately:
I Entered: "49.87852887698372, 8.694581847721706" and later the image was located around: "49.877478686435154, 8.692382293498092"
I got the cameras GPS coordinates in the exif, and converted them (via tool) to: 49.785266, 9.013798.
Now it's still at: 49.78635149999999, 9.0125739 (in 360 cities).
I hope I remembered the procedure correctly.
3) My latest addition is where I expect it to be.
Therefore, if you don't see an immediate user errors here, don't bother too much. I'll document my next few additions and report back, if it should happen again.
Thank you