The idea is simple. The problem with many images is that there are way to many files. Then why not put them in a slow moving video.
Said and done. You need the software ffmpeg or similar for this to work.
Could be good for sending many photos in an email. The compression with h.265 is excellent. I just compressed 1321 photos to 41MB. Though at lower resolution. 800×600 pixels. Another good thing is the transfer speed from a slow HDD is much faster. Sending a single file is much faster than transfering 1000+ different files.
To extract a single image. Just take a screenshot with the videoplayer or some other software.