Common use cases

Extract point-in-time frame from video

ffmpeg -i input.flv -ss 00:00:14.435 -vframes 1 out.png

Extract frame every second from video

ffmpeg -i input.flv -vf fps=1 out%d.png

Create timelapse video from images

ffmpeg -framerate 1 -pattern_type glob -i '*.jpg' video.mp4