So, i disabled everything except jetpack and it the same:
https://ewelt.org/blog/foto/saechsische-schweiz-in-einem-tag-teil-i/
I I wrote above, if I add in related posts to the image tag two parameters width=”xxx” height=”xxx” it works fine.
I think, the problem is, if jetpack does not fine width=”xxx” height=”xxx” in image tag on parsing post entry they thinks there isn’t any images in post.