Can't preview jpg files in the preview pane -- Windows 10 Fall Update (1709)

Finally found the solution.

Now that Windows 10 has nearly removed the old Control Panel; several items which are only available via the Control Panel are harder to find.

Open the old Control Panel; type into the Win10 Search Field "Control Panel" and then click the result to Open it. Make sure the Categories option is set; then click on Appearance and Personalisation; then File Explorer Options.

A new window will open -- click on the View tab.

The first choice "UNCHECK" Always show icons, never thumbnails.

I have now also found this same setting in the View Menu of Windows 10 File Explorer. At the far right-side of the header ribbon after clicking on the View Tab is an icon labelled Options.

Clicking this -- select the first choice "Change Folder and Search Options. A new window opens. Click on the View Tab; then again UNCHECK the first choice "Always show icons, never thumbnails."

There is an easy solution for this. Copy (not cut) the images without preview and paste them back in the same folder. Now you will get the preview and can delete the originals.

My problem is not related to file association, I've tried changing file association to multiple programs, including MS Paint.  To clarify, my problem is with jpg files not displaying in the File Explorer preview pane and has nothing to do with file icons.

I've discovered the problem is related to the new 1709 update feature "OneDrive Files On-Demand".  The problem with jpg files not displaying in the File Explorer preview pane only occurs for files that are on OneDrive with "Files On-Demand" enabled.  I have some files & folders specified as "Always Keep on this device" and I expect files to be displayed in preview -- and they are except for jpg files.  Other file types (pdf, txt, docx, xlsx, etc.) preview without issue.  jpg files on disk only and not on OneDrive ARE displayed in preview, the problem is only for jpg files on OneDrive, even though "Always keep on this device" is enabled.

If "Files On-Demand" is enabled and "Always keep on this device" is not enabled (files are in the cloud only) then no files are previewed (makes sense).

I have another computer that was just updated to 1709.  The "Files on demand" feature has not been enabled so all OneDrive files are on disk.  It displays jpg files on OneDrive in preview without issue.

To summarize my problem as I see it...  jpg files on OneDrive are not displayed in File Explorer preview if and only if "Files On-Demand" is enabled, even though those files are kept on disk.

Check which application is associated with JPG files. Right click on a JPG file, select "open with" menu option, then "Choose Another App" from the child menu which appears. 

Ensure you are using the "Photos" application. 

I suspect you have installed another graphics package such as paint.net and it has taken over the file assocation.

Problem is that Explorer need to get that application to render the image for display in the preview window, and if it cannot do so the preview window will remain blank.

I finally fixed it!!

Since OneDrive was mention in other replies and I too use OneDrive, I went into OneDrive and unchecked "Save space and download files as I need them".  As soon as I did that (no restart needed), the thumbnails loaded for every image in every folder!!

Can't believe it was that simple, yet the Microsoft Team couldn't/didn't figure it out and post the fix on any of the 50 or so threads with the same problem, and that I've scoured looking for the fix!

SMH . . . Another corporation that our money and support has made too big to be bothered with us.