Plug in your phone using the USB cable, pull down the notification shade to change USB connection mode to file transfer, then find your phone using your computer's file browser. Pictures should be in the DCIM folder.
You should enable USB debugging when you connect your phone to laptop. And use a data transfer tool like Airdroid or MobiKin Android Asisstant, you can transfer photos, videos, texts, contacts from your phone to pc easily. This is my way to backup phone files.