It has proved that the camera is really good at capturing colour and 3D images.
When the spacecraft reaches Mars, it will be able to orbit the planet at a distance of around 300km (186 miles) from the surface.
The picture of the Earth and moon was taken much further away than that, but you can still see the blue of the Pacific Ocean and white clouds.
The scientists are hoping the Mars pictures will be much more spectacular.
Mars Express is due to arrive at the Red Planet in December.
It's carrying the British-made Beagle 2 lander, which will test for signs of life on Mars.