Use your file manager to navigate to a folder named DCIM and see if they're in there. Failing that, they may have been put into an Android equivalent of Windows Recycle Bin and that's named Lost.Dir.
If you can't find File Manager or My Files, plug the device into your PC using a USB connection and use Windows to go through the folders.
If that doesn't work, go into the phone's Settings, then More and About Device. Tap that seven times and you'll see a message "You're now a developer". Go into Developer Options and put a tick in USB Debugging then try connecting to your PC again.