Images display differently using different browsers

I posted and received a reply at https://ww.wp.xz.cn/support/topic/images-displayed-in-chrome?replies=3#post-7481678

and was asked to post here.

The answer given in the post above is that the fix would be a css fix rather than a theme fix. If you might possibly be able to recommend what css is needed to make the images display consistently that would be very much appreciated!

You can access a page with the image problem at https://classroomxl.com/vba1-extaccess/?csid=1
via login using id: scuser1, pw = bsmith