This plugin (fit_screen) is wonderful, especially if you remove the intermediate pictures from Coppermine to save space, this plugin allows you to adapt the full image to the screen size, so you can see it in a whole. But how does it work? The functioning that allows this to happen is a simple code, you can easily add to your theme style.css and there’s no need for a plugin.

.display_media .image {
max-width: 100%;
height: auto;
margin-right: 0;
margin-left: 0;
}

That’s it!