It is the original graphic which was used for the R'lyeh hero, yes. Somebody posted this years ago, too, together with the scientific name, maybe it was on the Dom2 forum. There are a couple of other graphics that you can find online on the first result pages of Google Image Search which KO used as basis for some units.
I feel old. A lot of new threads that I see popping up, I always want to say "somebody posted that before!", the one before that was vfb's "Playing turns on a network server" tip. I already suggested this a couple of times!
