Seems to me that your thumbnails were probably pulled because the painted on bikini was considered a "'Censored" image:

Quote - No "Censored" language/images (some examples: "Warning: Nudity Inside" or black bars covering breasts/genitals)

w/ the painted bikini being equated to a 'black bar'.

I'd personally rather see nudity in the thumbs of pictures that contain nudity.
Anything else is misrepresentation of the full image, IMO.

As for quality vs. # of comments/rating: Any relationship between the two is purely coincidental. That's just my opinion too.

Friends don't let friends use booleans.