What YouTube asks for
- Size: 3840 × 2160 pixels for a video and 2160 × 3840 for a Short. Smaller works, down to 640 pixels wide.
- Shape: 16:9 for a video, 9:16 for a Short.
- File: JPG or PNG.
- Weight: up to 2 MB from the phone app, up to 50 MB from a computer.
- Account: custom thumbnails need a verified channel, and a Short's can only be added in YouTube Studio on a computer.
The part people forget: it is tiny
Most viewers meet your thumbnail about the size of a matchbox - in a search list on a phone, or beside a video that is already playing.
The preview draws it at both sizes.
If your face or your words are hard to read at the small one, they are hard to read for most of your audience.
YouTube also prints the video's length in a bottom corner.
Anything you put there gets covered, so the preview puts a time stamp there too.
What we would do
- Three words at most. A thumbnail is looked at, not read.
- One face, big, showing one feeling.
- A color that stands out against both YouTube's white page and its dark one.
- Write the title after the thumbnail, so it adds what the picture cannot say.