Hi When I was viewing my photos with Windows 7 Photo Viewer, it was very slow, it was loading for every photo. Then I found a fix for it.
It is because of the Calibrated Color Profile created by Windows 7.
If you remove it every thing will be fine.
Follow these steps
1. Right Click on Desktop and select 'Screen Resolution'.
2. Then Select 'Advanced Settings'
3. Select the 'Color Management' tab and press the 'Color Management..' button in properties window.
4. In the Color Management window, Select 'All Profiles' tab and scroll to 'ICC Profiles'
5. Select any profile with the name 'CalibratedDisplayProfile' and Remove it.
6. Thats it Close all open windows.
Now reopen the pictures folder, check the photos with Photo Viewer it will be lighting fast...
Let me know, if this helps you :-)......