How can i take off the highlight effect on < img >'s with links?

I want to remove the white overlay affect for all < a > anchor images with links. I want to do it globally.
Q. Where is the GLOBAL settings to remove all of the highlighting features wrapped around any imported
< img > with a link?
Is it a :hover rule in the CSS, or done with Javascript. My hunch is it’s in the CSS.
Yes, I’m aware of the noLightbox rule, but I want to remove it globally, not individually for each image I assign a link. It’s a lot less work to do it globally than to assign custom CSS properties for all images.

Sorry, but I do not have a website link because I’m working on Localhost. A link is irrelevant anyway because I want to remove the settings globally for all links on images. Thanks for your help.