Unlike the Samsung Note 4 which had a menu for turning on screen capture whilst playing back videos to easily grab an image from your video, all these options are missing on the Samsung Galaxy S6 or S6 Edge.

But it still can be done. The reason for selecting photos from a 4K video is that each photo grabbed is a 8mp shot. This is often a good way to capture moving targets (kids, pets) and select the exact frame you want as a photo.

So start playing your 4K video. Select top right “more” and change playback speed to its lowest setting. Now play the 4K video until you get to the part you want to capture as a photo(s). Press pause. Tap screen to remove on screen controls. With your palm swipe across the screen to take a screen shot. This will save a 8mp shot of the frame as a PNG file.

If you have found a better way then please let everyone know below in the comments.