Io. Galileo spacecraft image of Io, one of the moons of Jupiter, centred on the Media Regio region. Io is brightly coloured due to the presence of various sulphur compounds on its surface. This image was acquired by Galileo on 25 June 1996 at a range of 2.24 million kilometres; the smallest visible features are 23 kilometres across. Comparison between this image and those acquired by the Voyager spacecraft in 1979 show that the surface has changed in the intervening period. Changes include the greater prominence of bright areas on the right edge of Io, and large- scale changes in surface detail around the Masubi volcano (white, at lower centre).