Do you want to preview a YouTube video before playing that? Preview with multiple thumbnails is available on the video hosting website but to do that, either you will have to open the video on YouTube.com or on the webpage where the video is embedded. To see the thumbnail preview, you need to hover your mouse on the player status bar. Now there is an extension which enables you to preview a YouTube video through multiple thumbnails by just hovering the mouse on the link to the YouTube video, that link may be on any website or webpage.

YouTube Previewer is a Google Chrome extension which allows to see the preview of the YouTube video by sliding the mouse cursor on the link to that video. For example, to see the preview of the video which is available on the link attached below, you just need to hover the mouse on this link and slide a little in left-right direction on the link only.
Link to the video – trailer “The Island”
This extension is fetching the same thumbnails that YouTube shows on the player status bar for the video currently playing on the site itself. Once you enable the Chrome extension on your Google Chrome browser, the browser start treating the link as the player status bar and show all thumbnails of the linked video. You get options to change the quality of thumbnail images that the browser fetches from YouTube. This will definitely affect the image or preview thumbnail load time.
Do you find this Chrome extension helpful?