Create a mouse hover action for images

Is there a way to create a CSS shortcut to make a “Single Image” have an action like a button when a mouse hovers over it? It could move a little or go opaque, for example? I use images as links and I’d like that to be obvious with a mouse hover.

I’d love it to be something I could add to the “extra class name” for the images I want to do this to because I don’t want it to happen for every image.

Thank you so much for your help if you can swing it!