Get a PCloud account and install their app on your phone. Then you can go to your hidden folder and select all the pictures and send to your PCloud folder.
You can protect the app in your phone so it will only load with password.
Once the pictures are on your PCloud account, you can login in their website using the computer and download all.
If you can select the hidden photos in the photo app then I would try LANDrop. You will need to install it on both devices and have it running on both.
You select the pics you want to transfer in the photo app then access LANDrop by using the Share button (the up arrow in the box). It is the one you press to attach pics to emails, messages etc.