is this a Gutenberg block or an Elementor component? Can you clarify how you are adding the image?
It is definitely not Gutenberg. when I write a new post, there used to be a field below it where I could choose the header image, now only the header image settings remain, but no option to choose it.
I have made a screenshot of that section https://postimg.cc/XGC9TT0R
I am not really familiar with all this, I just got this page dropped on me to look after, but this issue is really bad, because new posts only get gray background.
the website is http://www.lbba.lt
Thanks
It looks like you are using Visual Composer you can find their help forum here
https://ww.wp.xz.cn/support/plugin/visualcomposer/