If you import the video into something like LR or PS... I am sure you can get a still from that. However, quality of the still is a different subject. I am not a fan of the GoPro stuff. They are ranked below most newer smartphones in IQ.
Oh ok. Thanks for the info. Just the thought of flying a drone to take 4k vids and just pull stills from the vid seems like a good idea. If you guys have time check out @copterpilot on Instagram. That's how I thought of pulling stills from a 4k vid.