Uses YouTube's storyboard to show preview images when hovering a video's thumbnail. Hold shift while clicking to jump to the time shown in the preview image.
You need to have a UserScript extension (e.g. Tampermonkey for Chrome, Greasemonkey for Firefox) installed to run this script.
YouTube's inline playback feature interferes with this script. To disable this feature go to Settings > Playback and performance and disable Inline playback.
These two scripts really helped me find my way around YouTube's storyboard feature:
- youtube-storyboard by bulutcy
- YouTube Storyboard Bookmarklet by Amit Agarwal