Some evidence: here is a photograph, as shown in OSX using Preview:
And here is the same image, as viewed using eog on Linux:
Notice the difference? Here are details of the displayed images, blown up 4x:
It appears that the blur issue is well known, though not something Apple seem interested in addressing. Presumably in Apple's official worldview, those working with photos who wish to see them without blur should be importing them into iPhoto or Aperture, and managing them with that.
The only workaround given is to copy the version of Preview from an OSX 10.4 machine, modify its version information to run on OSX, and use that. Which, quite frankly, is not good enough.