NASA
Nasa: Great Images in Nasa
Fascinating collection of images from NASA, chosen for their historical or aesthetic significance. Images are searchable by subject, by NASA center, and by keyword, and each is available in three sizes. With links to more information...
Curated OER
Science Kids: Science Images: Earth Horizon
This beautiful NASA image taken from the International Space Station as it makes its way over the Pacific Ocean shows the Earth horizon illuminated by light from the Sun.