YouTube Shorts thumbnail size: the official 9:16 specs
YouTube's help page recommends a 9:16 Shorts thumbnail of 2160 x 3840 pixels, with a minimum height of 640 pixels, in an image format such as JPG or PNG under 50 MB, uploaded in YouTube Studio on a computer. A 16:9 image on a vertical video is replaced by an auto-generated 4:5 thumbnail on the home, explore and subscription pages.
The official Shorts thumbnail specs
| Item | YouTube's recommendation |
|---|---|
| Aspect ratio | 9:16 (vertical) |
| Recommended resolution | 2160 x 3840 pixels |
| Minimum | 640 pixels tall |
| File type | Image formats such as JPG or PNG |
| File size limit | 50 MB when uploading from a desktop |
| Where to upload | YouTube Studio on a computer |
| Account | Must be verified |
How to add a custom Shorts thumbnail
Sign in to YouTube Studio on a computer, open Content, choose the Shorts tab, go to the Short, and under Thumbnail click Upload file, then Save. YouTube says custom thumbnails for Shorts are currently only available to add this way, on a computer.
What happens if you upload a 16:9 image to a Short
YouTube's help page says a vertical video with a 16:9 custom thumbnail is replaced by an auto-generated 4:5 thumbnail on the home, explore and subscription pages. Your 16:9 custom thumbnail still appears on the watch feed, in watch history and on non-mobile platforms. So where viewers meet your Short in those mobile feeds, a 16:9 file is not the one they see.
Why guides disagree about Shorts thumbnail size
Guides do not agree. Timeskip lists 1280 x 720 at 16:9 as the Shorts thumbnail spec, while Vista Social lists a 9:16 ratio at 1920 x 1080 (read 2026-10-04); 1920 x 1080 is a landscape pixel size, so those two numbers do not describe the same shape. YouTube's own page, read on 2026-10-04, says 9:16, 2160 x 3840, minimum 640 pixels tall. When guides disagree, follow the help page.
A short checklist
Use a 9:16 image. Export it as JPG or PNG. Keep the key subject in the middle so crops do not cut it. Upload it from a computer. Confirm your channel is verified first.
Where ThumbnailMaker fits
ThumbnailMaker outputs 1280 x 720 (16:9) thumbnails, so it is the right fit for your standard widescreen videos and for the 16:9 version that shows on the watch feed and on desktop. It does not produce 9:16 files, so a vertical Shorts thumbnail needs a design made in another editor.
Sources
- YouTube Help, "Add custom thumbnails on YouTube": https://support.google.com/youtube/answer/72431 (read 2026-10-04)
- Timeskip, "YouTube Shorts thumbnail size": https://timeskip.io/blog/youtube-shorts-thumbnail-size and Vista Social, "YouTube Shorts thumbnail size": https://vistasocial.com/insights/youtube-shorts-thumbnail-size/ (read 2026-10-04, cited only to show that guides disagree)