You could wait until the cows come home for Googlebot-Image to ask for robots.txt in its own name. But all the different googlebots talk to each other, so I think the question is whether richsnippets considers itself a robot or not. Yes, yes, OK: whether the humans who programmed it included a directive to obey robots.txt.
The name suggests it comes down on the "robots" side. (Preview and Translate don't. In the case of Translate, I've verified this by direct experiment. In the case of Preview, a loaded htaccess still beats a robots.txt file.)