Connect the cable that should have come with the phone to your desktop's USB port. Pull down the notification bar and look for Android System - USB charging this device. Tap that, tap again and choose MTP. Then you should see the G6 in Explorer in your PC. Open it and you'll see folder(s) and/or files. Pictures should be in DCIM/Camera.
PC or Mac? If it's a PC then your computer can read the phone as if it was a USB drive, you just have to tell it that you want that. After you connect the phone via cable to your PC, swipe down on the Android phone and expose your notifications, scroll down to the bottom and you'll see Android System, click on it, to open the notice, THEN click again and you will see options, you want the 2nd one "Transfer Files"
HOWEVER if you have a Mac then you'll need a special program called Android File Transfer, PLUS you have to do the stuff mentioned above. Here's a link to that app and instructions.