Just like an Iris... (Natural Colors; credits: NASA/JPL/Space Science Institute

Caption NASA:"Rendered in myriad hues, vivid details of Saturn's stormy Atmosphere play out below the shadow of the Rings. A well defined storm swirls through the atmosphere of the southern hemisphere in the lower left of the image, like the tight blue circle of an eye's iris.

This view looks toward the sunlit side of the Rings from about 36° below the Ring-Plane.
Images taken using red, green and blue spectral filters were combined to create this Natural Color view. The images were obtained with the Cassini Spacecraft wide-angle camera on Dec. 29, 2008 at a distance of approx. 1,1 MKM (such as about 680.000 miles) from Saturn and at a Sun-Saturn-Spacecraft, or Phase, Angle of 51°.
Image scale is roughly 60 Km (about 37 miles) per pixel".