Remove box-shadow from image

Hello,
with CSS I set up a light shadow for all the images in my content area. I have one page where I want to remove the box shadow of one or all images. I know this would work if I give one image an ID or several images the same class. On the page I want to remove the box-shadow I use the beaver plugin and it’s built-in option to give the image an ID.
Link to page

My problem is know that I don’t know how to overwrite the general rule. I tried with !important, but it doesn’t work. It seems that I don’t have the right selector.

Can someone help me to find the right selector, please?

Kind Regards,
Michael