The Future of Thumbnails for Shorts

The ideal length is as short as possible, but no shorter than you need for the story. There's so much competition for attention that people can increasingly tell if a video is filler or not interesting enough to get them to watch through. People are getting more and more sensitive to that. Some chapters can show you where people would have just abandoned your video before, but because they see something interesting in a later chapter, they're willing to skip to that chapter. That's an indicator that maybe the video is too long or notinteresting enough to get their attention.