I've now washed (cold water) and machine-dried the cotton/bamboo rayon Spoonflower fabric. The original length of 2 yards exactly (72" or 183cm) has shrunk to 69.25" (176cm). That's about 3.8% shrinkage, which seems a fair amount to me. The printed width, post washing, is 51.5" (131cm) - Spoonflower's site says the printable width is 52" so I think it shrank a small amount in width too. That's after pressing it with steam - the unpressed fabric was drawn up so even shorter.
The other thing that happened in the wash was slight crocking of the flat dark-grey background, as you can see here. I don't mind it as it gives a slight texture to the previously completely unvaried background - makes the grey look more like the rock you would scan for a trilobite fossil.
I wrote that last sentence, and then went looking on Google for pictures of trilobite fossils from this area. My gosh, I was right! Check these out!
I think I'm going to make it up in a much-used men's casual shirt pattern, the very long out-of-print McCalls 4115.