To quote myself from something left out of the interview:

I wonder that no one has asked yet about the image on the cover because it's an interesting story. Basically, we pinched it out of a rancid old beer-soaked encyclopia we found on the floor of branch of Wetherspoons in Preston one day we were talking about the cover of the album. Picking it off the floor it fell open and here's this perfect image which reminded us of the cover of Unknown Pleasures but had the text from the other side soaking through like some wierd Da Vinci code, so we took it home and scanned it and worked on it on the computer until it's full glory & inner mystery was revealed. On one level it's secular & scientific, but on another it's folkloric too, the World Tree as a Mythological Archetype, Ygdrassil, or just the same old tree in which the Porcupine sits looking keenly to some unseen horizon. On the top, however, sits the Squirrel and the Owl with a Bat & Bird flitting around, far above the spermatozoa & discarded novelty condoms that wash around at the bottom. But what does it all mean? Something along the lines of : Life is Splendid - and nothing ever happens without being the consequence of that which went before; and that Tradition is alive and well in everything we see and touch...