That's the illustration that my partner Isabelle came up with for the very last spell in the book, stone to flesh. Now, a couple things that I like about this "Easter Island" looking fellow, inspired by that spell: it's a little ambiguous exactly what would happen if you cast stone to flesh on him. Is the implication that it's a trapped giant who then comes back to life and serves you? Can the spell give animation to a huge statue and possible answer questions from the party? I actually want to give DM's some amount of flexibility and authority in interpreting those kinds of questions, particularly so for spells at the maximum level -- and if I or they are inspired by a work of art like this, so much the better. Plus, he echoes the "great stone face" of the Original D&D Greyhawk supplement -- which Isabelle has never seen.
Here's my current rules text for the stone to flesh spell. Note that there is no allowance for a "reversed" usage of the spell; in OD&D it's the only magic-user spell that seems to imply such usage, and I thought it much cleaner to just remove that complexity from the system (if you want a different effect, then research a different spell).
Stone to Flesh: (Range: 12 inches, Duration: Instant) This spell restores any petrified creature to its normal state. The spell can also convert a mass of stone into a fleshy substance; such flesh is inert unless a life force or magical energy is available. The caster can affect a mass up to 3 feet in diameter and 10 feet long.
The funny thing is that prior to Isabelle's illustration, I had the spell much shorter; it simply said, "This spell restores any petrified creature to its normal state," and I'd cut out the other usage that comes from AD&D/3E SRD. But seeing Isabelle's vision for the spell, I decided I really wanted a figure like that to be affected by the spell. Will it have some "life force" or "magical energy" available for it to speak or act? Or maybe it's just a big slab of meat to use in some more profane way? The DM gets to decide within the given parameters of the spell. At the topmost levels, I think there should be a little mystery in your campaign (at least until your players put their magic to the test).