Quick answer: the recommended YouTube thumbnail size is 1280 × 720 pixels in a 16:9 aspect ratio. YouTube also generates smaller versions of every thumbnail automatically. To save one, paste the video link into the YouTube thumbnail downloader.
Recommended Upload Size
YouTube recommends uploading custom thumbnails at 1280 × 720 pixels with a minimum width of 640 pixels, in JPG, GIF or PNG format. Keep the 16:9 ratio so the image is not cropped or letterboxed, and check YouTube's help pages for the current file size limit, as it has changed over time.
Every Size YouTube Generates
For each video, YouTube creates thumbnails at several fixed sizes that are available at predictable URLs, such as https://i.ytimg.com/vi/VIDEO_ID/maxresdefault.jpg.
- maxresdefault.jpg: 1280 × 720, the largest size and 16:9.
- sddefault.jpg: 640 × 480, a 4:3 frame that can include black bars.
- hqdefault.jpg: 480 × 360, also 4:3 with possible black bars.
- mqdefault.jpg: 320 × 180, a small 16:9 image.
- default.jpg: 120 × 90, the smallest, used in lists.
Why the Maximum Size Is Sometimes Missing
Not every video has a maxres thumbnail. Older uploads and videos uploaded in lower resolutions may only have the smaller sizes. A tool that checks each size, as Toolbantu's does, shows you only what exists instead of giving you a blank or placeholder image.
Design Tips for Thumbnails
- Design at 1280 × 720 but check how it looks at 320 × 180, since that is closer to how many viewers see it.
- Keep text large and to a few words, and leave the bottom-right corner clear for the video duration badge.
- Use strong contrast between text and background.
Using Someone Else's Thumbnail
A thumbnail belongs to the video's creator. Saving one for reference or commentary is common, but reusing it elsewhere may require permission. If you need a different size, use the image resizer, and shrink the file afterwards with the image compressor.