Overlay “Zoom” icon over wp-caption images?

Bump!

Yes, it’s doable:

div.wp-caption {
position: relative;
display: block;
}
.wp-caption a[href$=”.jpg”]:before {
content: url(magnify.png);
position: absolute;
right: 20px;
top: 20px;
}

See https://soukie.net/2009/08/20/typography-and-css/#example for more details and example. I am actually using :hover:before. Plus you might need to extend the list of file types but that’s simple.