I guess all the files are stored in the phone memory now and we can't access them on computer directories. That means you can't find the photo files when you connect your phone to PC.
You can try to find it on your computer, connect your phone to PC via a USB cable, and ento into DCIM folder, if you still can't find the photos, unfortunately, you may have lost them during the update.
Yes, you can't access the files downloaded on a site directly on your phone storage, but I think you can open it when it finishes downloading, it will pop up a window, just click it to see the file
If your files are stored in the phone memory, you can't see the files on your PC by just connecting your device via a USB. It only works for files on SD card.
In order to recover lost data from Android, you have to root your device first, if didn't, the recovery tool will also root your device in the recovery process.
Two solutions introduced: one is using Android transfer tool to export from one to PC and then import into another, the other one, using phone to phone transfer tool to copy data from one to another.
Both are useful and need a professional transfer tool.