In this Video Panasonic's Tech Team Provides you with a quick explanation on how to use the 4K 6K Photo mode.
With 6K Photo, you can take a high-speed burst of pictures at 30 frames/second and save the desired pictures, each made up of 18 million pixels (approx.), extracted from their burst file.
With 4K Photo, you can take a high-speed burst of pictures at 60 frames/second and save the desired pictures, each made up of 8 million pixels (approx.).
The model shown in the video is the LUMIX DC-GH5, the information in this video also applies to LUMIX DC-G9