The moon that appears from the left is Io. Seeing that night was about 5-6 and video frames of Ganymede were carefully selected. The brightness contrast between Europa and Callisto is real. The relative brightnesses of the other moons is approximate. It appears to show surface markings.
Filters can make a big difference on the appearance of Jupiter's clouds.
Longer red wavelengths penetrate deeper into the Jovian atmosphere. The image on the right is among the best I've obtained. Longer wavelengths are also less affected by Earth's atmospheric turbulence. Use of a red filter can potentially yield higher resolution images. The right image is a high resolution simulated view of Jupiter made by the Casinni spacecraft on December 7, 2000.