Hmmm, I was just looking at an image — NASA – Earth’s Horizon:
Airglow above Earth’s horizon and solar array panels add color to this scene of a portion of the International Space Station as the orbiting complex is docked with the Space Shuttle Discovery.
I clicked the link to the large version (650Kb) and an image about 3,000 pixels by 2,000 appeared, but it didn’t fill the window, as you might expect. Instead it fit the window, with room to spare and the cursor turned into a plus sign. Click: the image enlarges and the cursor turns into a minus sign. Click: the image reduces.
Nifty. Thanks Leopard.