Always horizontal scrollbar if a image is on the site


my problem is, when I load header and footer on the site - the width of the site is correct.
But if I place an image - the site is a little bit scrollbar horizontal.
I have placed the image in a div - the div has owerflow hidden - the problem is not only when the image is very large - it is also when the image is only 5px…

I don´t know what the problem is - i have checked it on a “new” site - there is not the problem - so is the failure in an update or something? I hope you can help me

you can only see it if you go to the website normally:

Here is my site Read-Only: