Nico, it's not a photographer's account.  It is an illustrator's.  Now that I've examined your example, I have no faith whatsoever that those brilliant illustrations in his portfolio are entirely his.  If he made a sillhouette out of your cricket player, I can't believe that he made any other figure from scratch.  It dissapoints me bigtime.   I had to hold back from posting a comment to the image that said "YOU THIEF!!! YOU STOLE THIS FROM NICO SMIT!!!!!"

If he only had a few in his port, I would think that oh, he's a beginner and doesn't understand copyrights etc.  This guy has 98 pages of illustrations!  He knows exactly what he's doing!!!!

Yes, I say do something.  I don't know what...  I'd think go straight to StockXpert (98 pages of illustrations...)

Looks like a direct rip off to me. I would report it direct to StockXpert. I would also look for this image at other agencies and report it where relevant. Inspiration is one thing, this is just theft.

yes I would report it.

quote from istock

"If you require a foundation to plot your points in Illustrator, ensure you are the original creator of the artwork/photograph/sketch/render/scan that you base your work on. Any illustration found to be based on work from outside sources (i.e. found art, images found on the Internet, other artists� work, magazines, clip art, etc) can result in a suspension of upload privileges."

http://www.istockphoto.com/illustrator_5.3_traces.php

and more info from istock

http://www.istockphoto.com/illustrator_8.1_derivative.php

I don't think it is 'illegal' (perhaps yingyang has something to say here) but I know it is not an accepted practise for the micros.  I would let dreamstime, and stockxeprt (and other sites) know... as well as the artist himself.