Blind Ape Seo

I got a question from one of my readers on my post Optimizing image search traffic :

Yes, helpful post indeed. A question - once you are getting traffic from images, can you tell what keywords are driving the traffic using Google Analytics? Using GA, images.google.com is treated as a referring site, without any information about the keywords that found the image. I’d like to know what keywords the image is being found on.

My answer:
As far as I can see, keywords gotten via image search are shown / counted as normal keywords.

The real world example I am basing this on:
One of my sites is getting a lot of hits via the keyword “Schnörkel”, which means something like flourish or embellishment.

This word does NOT appear anywhere on the page except for being the name of a small divider gif.

PS:
In that case, I renamed the image to div1.gif, as the traffic for that was no traffic I particularly cared about.