This is pretty amazing. Uploaded to NASA's Flckr stream just two days ago, this is "the first ever image of Earth taken from the surface of a planet beyond the Moon," snapped by the Mars Exploration Rover Spirit in 2004.

First Ever Image of Earth Taken from Mars

(Click on the image to enlarge it.)

NASA gives further details on its Flickr stream about the image, including the following:

The image is a mosaic of images taken by the rover's navigation camera showing a broad view of the sky, and an image taken by the rover's panoramic camera of Earth. The contrast in the panoramic camera image was increased two times to make Earth easier to see.The inset shows a combination of four panoramic camera images zoomed in on Earth. The arrow points to Earth. Earth was too faint to be detected in images taken with the panoramic camera's color filters.

[NASA]