The original .png file of the above was posted on Computers Club Drawing Society.
Initially it was on a spare, light blue background but then I decided it needed something like the surface of Venus.
Seeing Rick Silva's "En Plein Air" show at Transfer Gallery and the large-format 3D landscapes on his blog inspired me to enlarge the above to 800 x 800. Am generally not a bicubic smoothing fan and am still weighing whether the scale boost adds anything.
Update: Decided to take down the 800 x 800 enlargement I originally linked to here. It's been replaced with another CCDS drawing that was made for that scale, rather than just blown up for effect.