You spend hours on a thumbnail, and the moment it goes live, YouTube slaps the video's duration in a corner. No big deal if you planned for it. More annoying if that's exactly where you put the face or the key word.
Four things YouTube puts on top of your image
None of these elements are in your file. So you don't see them in Photoshop, but your audience does. Starting from the top:
- Top right, the hover icons: on desktop, when someone moves their mouse over the thumbnail, YouTube shows buttons like “Watch later”.
- All around, the rounded corners: the corners get trimmed, so anything pushed into a corner loses a piece.
- At the bottom, the red bar: on a video someone has already started, a bar shows where they stopped.
- Bottom right, the duration: the trickiest spot, because it's there everywhere, all the time.
The official formats
| Video | Short | |
|---|---|---|
| Aspect ratio | 16:9 | 9:16 |
| Recommended size | 3840 × 2160 px | 2160 × 3840 px |
| Minimum | 640 px wide | 640 px tall |
| Formats | JPG or PNG | JPG or PNG |
| Max file size on desktop | 50 MB | 50 MB |
| Max file size in the mobile app | 2 MB | Desktop only |
Source: YouTube's official Help Center. Two extra conditions: your account has to be verified to add a custom thumbnail, and a Short's thumbnail can only be added from YouTube Studio on desktop.
Your thumbnail will be tiny
YouTube doesn't show your file as is: it makes smaller versions of it depending on the screen and the placement (home, search, suggestions, phone, TV). Very often, your thumbnail ends up just a few centimeters wide.
Before you export, run a simple check: send it to your phone, drop it in small into a screenshot of the YouTube home page and look at it from a distance. Three questions:
- I can tell what the video is about without reading the title
- The text reads effortlessly
- The main subject stands out from the background
A single no is enough: simplify before you polish.
Export traps
- Any ratio other than 16:9: a square or 4:3 image won't fill the frame.
- Elements close to the edges: between the rounded corners and the downscaling, they get lost.
- File size on mobile: from the app, the limit is 2 MB. A good-quality JPG gets through where a big PNG gets stuck.