The person responsible for the manipulation, Emily Lakdawalla, told a forum of excitable theorists that she made the changes because of the way Cassini takes photos.
"Cassini takes colour pictures by snapping three sequential photos through red, green, and blue filters," she said.
"In the time that separated the three frames, Dione moved, so if I did a simple color composite I would be able to make Titan look right, but not Dione; or Dione look right, but not Titan.
"So I aligned Dione, cut it out, and then aligned Titan, and then had to account for the missing bits of shadow where the bits of Dione had been in two of the three channels."
As we have cleared that out, next image please.