Backlit

The keyboard is backlit.

The only pictures there are of Tom are backlit, which in essence means you can only see him in silhouette.

The only pictures there are of Tom are backlit, meaning you can only see his silhouette.

After successfully entering orbit around Saturn, the spacecraft immediately began taking pictures from above the rings as they were backlit by the Sun.

Tom is backlit in this picture. That's why you can't make out his face.

a backlit computer keyboard