Guys, it's not an issue with the file association because he can open the images, the only issue that he has is with Image Thumbnails that are not showing up
Here is how to fix this:
Method #1
Start > in the search box, type Folder Options > press Enter key > click View tab > un-check "Always show icons, never thumbnails" > OK
Method #2
Start button > Control Panel > Classic view > Systems >In the left column, select Advanced System Settings > Performance tab, click Settings > Visual Effects tab, click "Always show thumbnails instead of icons " > OK