Indeed, that image is from Alex Tavoularis’ storyboards for the third draft (which is when the ideas I mentioned above were being mooted).
Leia being beaten up and bloody is mentioned in the same third-draft script – Carrie Fisher has remarked on how that detail was present in the script she got for her audition.
Both the McQuarrie thumbnail sketches above, and another unfinished Tavoularis sketch of a topless Leia, are included in The Making of SW. John Mollo’s words from the Costumes book also indicate the idea of THX 1138-style onscreen nudity was considered at one point, though it was never written down in script form.
Not that that’s surprising with GL, mind you – after all, Ralph McQuarrie also did a whole series of production paintings featuring a female Luke around the time of the second draft, an idea which similarly didn’t find its way onto the script pages.