White horizontal lines through PDF photos viewed with Preview

I have the same problem and haven't been able to find a reason for this.
Same happens if you view the file in Quicklook.
What is happening is that the image is been cut up into segments when the pdf file is created.
The same happens when the image is placed into Illustrator – you can see the lines in Illustrator.
If you open the pdf in Illustrator (after being saved as pdf) (embeded image) it is cut up into segments.
The white lines are the edges of segments. What is happening is similar to what happens when an AI file is flattened – images get cut up. This shouldn't be happening for a straight forward pdf.
Adobe may be able to answer this issue – I may look into it. Stephen

Same problem here. MacBook Pro (Mid-2007), Mac OS X 10.5.6.
Just experienced with a document (direct link: http://astrobotictechnology.com/wp-content/uploads/2009/Astrobotic%20MoonDigger% 20Report.pdf) with the following authoring info:

Acrobat Distiller 8.1.0 (Windows)
PScript5.dll Version 5.2.2

To solve this problem in Preview, go to preferences, click on PDF, and uncheck "Anti-alias test and line art". The white lines on photos will go away, however test will not appear as attractive.
There is no means to turn this off in Safari. If you save a file from Safari to your desktop and then open it with Preview or Acrobat you can view it without the lines. Acrobat displays both photos and test correctly on PDF's.

Same problem. I was able to download Reader and it solves the problem, but I'm interested in why Preview doesn't view the files correctly. Mine were originally made with Indesign and saved as a .pdf.