Hello SynergyQ,
You are stating that your photo library no longer shows the photo thumbnails, is that correct? I will try to assist you with this issue.
1. Open up the file explorer
2. Click on the organize button up in the top left corner
3. A selection box will appear you want to click on “folder and search options”
4. Click on the view tab at the top
5. Click the restore defaults button
6. Click apply and then ok
7. Close out of the file explorer and then reopen it
Let me know if that helps.