Problem when viewing DPR galleries
I noticed a similar thing with the samples gallery slideshow a few months ago and started a thread about it.
I included screen shots to illustrate the issue allong with my theory to why it was happening.
I found that clicking the fullscreen button in the slideshow solved the problem.
Of course in normal galleries there isn't this option but I don't know if regular galleries are effected by the same problem. Hopefully turning off zoom in your browser has resolved the issue but because what i found is related I thought id post a link.
I think amazon-dpreview should provide instructions for people to set there browsers up the right way, otherwise they are underselling the image quality of the cameras they sell.