Which application are you trying to view the JPEG in?
If its the Photos app, try resetting it.
Open Start > Settings > Apps > Apps & features
Scroll down to Photos
Select it
Click Advanced options
Click Reset
Restart
Check the Store for updates then check if you open JPEGs again.
Also, point to one of the JPEGs, right click it
Click Properties
Under the General tab, click Change
Choose Photos
Click OK
Click Apply then OK
Try opening the JPEG
If that does not work, right click the JPEG, click Open with, click Paint to see if it opens.