Are you able to see the photos in the iPhone? If so, importing them like LACAllen suggested should retrieve them. This is how:
Import photos and videos from your iPhone, iPad, or iPod touch to your computer - Apple Support
However your Photo Import wizard may need to be reset as previously mentioned. This is easy if you are a bit of a techie, if not you may not feel comfortable doing it. I have a Dell W10 PC and have done so before several times.
You would have to delete the PreviouslyAcquired.db file and it is hidden file. To find it go to Cortana and type %appdata% and then back up one folder from Roaming to Local then locate the file here:
C:\Users\[username]\AppData\Local\Microsoft\Photo Acquisition\PreviouslyAcquired.db
If this is too much mumbo jumbo, you should still be able to see the pictures using File Explorer. While not the ideal way to import (you would not get any edits) you can open File Explorer, click on the phone in the left panel, then expand all the subfolders under the phone. iPhones for better or for worse create new DCIM folders every month and if the pictures are there you should be able to locate all the DCIM folders. There may be many and it may take a while to locate all the pictures.