How to Download a YouTube Thumbnail in HD
The cleanest way to save a thumbnail is to use the public thumbnail file YouTube already serves instead of taking a screenshot of the player.
Three direct steps
Copy the standard video URL, Shorts URL, youtu.be short link or the 11-character video ID. Paste it into ThumbPull and choose PULL. ThumbPull checks the public thumbnail variants and shows only the files it can actually retrieve.
Choose MAX RES when it exists. If it does not, use the largest genuine variant available. A missing maxresdefault is not a broken tool and should not be replaced with a fake '4K' upscale labeled as if it came from YouTube.
Download saves the image, Copy URL gives the direct public thumbnail address, and Edit / Resize sends the same image into the image workspace without making you download and re-upload it first.