The Windows 7 Photo Viewer is a convenient feature for viewing full photos instead of just thumbnails. The Photo Viewer of Windows 7 allows for basic image editing tools like rotating the photos and zooming in/out for more preview detail. However, a small “bug” can slow down the performance of Photo Viewer. It causes the very slow loading an display of pictures – even those that are low resolution and file size. This bug that causes the slowdown of Photo Viewer is easy to fix.
Photos below show the slow performance of Windows 7 Photo Viewer when attempting to open a jpg wallpaper
It normally does not take 2-3 seconds for the second loading notice to appear and stay on the screen before the actual image is displayed.
The very nature of the Photo Viewer slowdown is a weird “bug”. It has been observed that users who have calibrated their displays and resolution settings through the Windows 7 -- Control Panel – Display Settings -- Calibration, have encountered the slowdown of Photo Viewer.
To remedy this peculiar “bug” in Windows 7 Photo Viewer, we will need to remove the monitor/display calibration file.
Right-click on the Windows 7 Desktop, click
Personalize, click
Display.
Click
Change Display Settings 
Click
Advanced Settings 
On the video card settings, click the
Color Management tab, then click on the Color Management button.
Here is the tricky part, remember and write down the filename of the ICC color profile.
Make sure that you have written/saved the exact profile filename.
No we will delete this ICC profile.
On the
All Profiles tab, select the text that is the exact ICC profile filename of we had saved earlier. Click
Remove
Choose to proceed with the removal of the ICC color profile.
Upon successfully performing the steps above, your Windows 7 Photo Viewer features will be much faster and clearer.
Tech details of the solution: It is guessed that the Windows 7 image calibration settings will try to apply in the Photo Viewer window. This causes the computer to apply the calibration settings of edited colors/brightness-and-contrast to the preview of Photo Viewer. This causes the delay and slow loading of the next queued pictures.
As always, it is best to use the calibration/setup tools provided by your hardware/software manufacturer. Download the latest drivers and save them in your compute for possible future use.
