Checked on October 4, 2026, based on the YouTube Help article "Add video thumbnails" (support.google.com/youtube/answer/72431).
You can add a custom Shorts thumbnail only from YouTube Studio on a computer, and your account must be verified. The mobile app doesn't support it yet.
Specs: regular videos vs. Shorts
| Item | Regular video | Shorts |
|---|---|---|
| Recommended resolution | 3840×2160px | 2160×3840px |
| Minimum size | 640px wide | 640px tall |
| Aspect ratio | 16:9 | 9:16 |
| Format | JPG, PNG | JPG, PNG |
| File size | 2 MB on mobile · 50 MB on desktop | 2 MB on mobile · 50 MB on desktop |
In practice many creators use 1080×1920, which is 9:16 and keeps the file small.
Why vertical (9:16)?
Shorts fill the whole phone screen, so the thumbnail should use the same 9:16 ratio. That way it shows without cropping in the Shorts feed, search results and on your channel page. If you upload a 16:9 image, it can be replaced with an auto-generated frame or shown with empty bars.
There is one more catch: if a vertical video has a 16:9 custom thumbnail, YouTube shows an auto-generated 4:5 thumbnail on Home, Explore and Subscriptions. Your custom image appears only on the watch page, in watch history and on desktop. So make Shorts thumbnails vertical from the start.
How to make one
- Open the YouTube Thumbnail Maker and choose the 9:16 (vertical) canvas.
- Put the most interesting moment or key phrase inside the central 60%. The top and bottom can be covered by app buttons (like, comment, share).
- Keep text to 2–5 words, large enough to read on a small screen.
- Save as JPG or PNG and check that it is under 2 MB.
- In YouTube Studio, go to Content → Shorts, open the Short and replace the image under Thumbnail.
Daily upload limit
YouTube limits how many custom thumbnails a channel can upload per day. If you see "daily custom thumbnail limit reached", try again after 24 hours. Community Guidelines strikes can lower the limit, so if you need to change many thumbnails, spread the work over a couple of days.
Good vs. bad
- Good: 2160×3840 or 1080×1920, key scene in the central 60%, not hidden by buttons.
- Bad: a 16:9 image squeezed into a vertical canvas so the top and bottom are cut off.
- Good: two or three big words that read on a phone.
- Bad: lots of small text that vanishes in the feed preview.
Common mistakes
- Uploading the 16:9 thumbnail of a regular video to a Short, so YouTube swaps it for a different ratio.
- Not verifying the account, so the thumbnail option never appears.
- Trying to change it in the mobile app, which doesn't support Shorts thumbnails.
FAQ
Can I change a Shorts thumbnail on my phone?
Not at the moment. According to YouTube Help, custom Shorts thumbnails can be added only in YouTube Studio on a computer.
Is 1080×1920 big enough?
Yes. It is 9:16 and well above the 640px minimum height. YouTube recommends uploading as large as possible (up to 2160×3840), but 1080×1920 keeps the file small and looks sharp on phones.
Why does my Short show a different thumbnail in the feed?
If the custom thumbnail is 16:9, YouTube shows an auto-generated 4:5 image on Home, Explore and Subscriptions. Upload a 9:16 thumbnail to avoid this.