The YouTube thumbnail size, and the size that actually decides the click.

Short version: upload 1280 by 720 pixels for a regular video and 1080 by 1920 for a Short. Then judge the thumbnail at the size people really see it, about 200 by 113 pixels in a phone feed. Most thumbnails are built for the big size and lose at the small one.

The numbers

Why 1280 by 720 is the wrong number to design for

YouTube stores the big file and shows a tiny version almost everywhere: the home feed, search, suggested videos, subscriptions, and the Shorts shelf. On a phone, your 1280 by 720 image is shrunk by more than six times in each direction. Three things happen at that size:

• Small text vanishes. Anything under about 9 pixels of cap height at 200 wide is a smudge. That is three to five big words, not a sentence.
• Small subjects vanish. A face that fills a fifth of the frame at full size becomes a dot. The subject should fill at least a third of the frame.
• Low contrast turns to mud. A dark shirt on a dark background looks like one shape. The subject needs to separate from the ground, with an outline or an opposite color.

This is a real 1280 by 720 thumbnail at its feed size. If yours does not read this small, the big version does not matter.

A quick way to check yours

Drop any thumbnail into the free checker. It shows the image at phone feed size and desktop size, scores subject size, face, separation, busyness and contrast, and tells you what to fix. No account, nothing saved.

The file itself

• Export at 1280 by 720 or 1920 by 1080 (Thumbnl gives you 1920 by 1080). YouTube resizes either; what matters is staying under 2 MB.
• JPG at high quality usually lands well under 2 MB. PNG is fine for flat graphics. Keep it under 2 MB or the upload fails.
• Keep the important parts away from the bottom right corner, where the duration badge sits, and away from the far edges, which get cropped in some placements.
• For a Short, export a separate 1080 by 1920 image. Do not stretch the 16:9 one.

Where these numbers come from

The 1280 by 720, 640 minimum width, 2 MB and file type rules are YouTube's own upload requirements. The July 2026 change that opened custom Shorts thumbnails to Partner Program channels is from YouTube's announcement that month. The feed size is measured from the YouTube app on a phone; it varies slightly by device, which is why Thumbnl scores at 200 by 113 rather than a bigger, friendlier number.