I wish I could offer some help but I am having the same issue. If I find a solution I will post it here.
I tried something in Windows Explorer and noticed a significant difference in the time it took a picture to load. You can try the following and see if it helps.
1. Open Windows Explorer
2. Click on Tools
3. Click on Folder Options
4. Click on the "View" tab
5. Make sure "Always show icons, never thumbnails" is checked.
6. Click on OK
Let me know if this helps.