1. Go to this website
https://www.get-youtube-thumbnail.com/2. Enter the URL of a Youtube video, press Get YouTube Thumbnail
3. It will show you the thumbnail, and return the URL of the thumbnail image
4. Create a reply in 4chins
5. Click post from URL
6. Enter one of the two Image URLs, such as
https://i3.ytimg.com/vi/2nIEDtxcji4/maxresdefault.jpg7. Hit Submit
Now you can get the thumbnail next to your post easily. Really useful when you are posting a link to a stream
https://www.youtube.com/watch?v=2nIEDtxcji4https://www.youtube.com/watch?v=2nIEDtxcji4https://www.youtube.com/watch?v=2nIEDtxcji4 