ShortsAIYouTube thumbnail size and requirements
Custom thumbnails must be 1280 by 720 pixels (16:9), under 2MB, in JPG, PNG, GIF or BMP. Minimum width is 640 pixels.
Export at exactly 1280 by 720 as JPG at high quality; a larger PNG is the usual cause of the 2MB rejection.
The duration badge covers the bottom-right corner and the watched bar the bottom edge, so keep text out of both.
What size should a YouTube thumbnail be?
1280 by 720 pixels, a 16:9 ratio. YouTube's minimum is 640 pixels wide, but a 640-wide image is upscaled on every screen larger than a phone and looks soft. The image must be under 2MB and in JPG, GIF, BMP or PNG. Those figures were checked on 2026-08-26 against YouTube's own help page.
Why does YouTube reject my thumbnail?
- Over 2MB. A 1280 by 720 PNG with a photo in it is often 2.5 to 4MB. Export as JPG at 85 to 92 percent quality instead; it will be under 500KB.
- Wrong ratio. A 1080 by 1080 image is accepted but cropped or padded to 16:9.
- Custom thumbnails need a verified channel. Verification is a phone number, not a subscriber count.
Why do thumbnails look blurry even at the right size?
YouTube re-encodes every thumbnail and serves it at several sizes, the largest being 1280 by 720. Blur comes from three places: an upscaled source, heavy JPG compression on fine text, and small text that survives at 1280 wide but not at the 168-pixel-wide version shown in suggested videos. Design for the small version: one face, three to five words, high contrast.
Where are the safe zones on a thumbnail?
The duration badge sits in the bottom-right corner, and once a viewer has started the video a red progress bar runs along the bottom edge. On mobile, the title and channel name sit below, not over, the image. Keep text away from the bottom-right and the bottom 10 percent, and remember that the whole image is shown at roughly 250 pixels wide in most feeds.
Does the same size apply to Shorts?
No. Shorts do not take a custom 16:9 thumbnail; the cover is a frame chosen from the vertical video itself. The 1280 by 720 rule is for regular uploads.
How do you generate a YouTube thumbnail with AI?
The YouTube Studio tab in ShortsAI generates a 1280 by 720 thumbnail from the video's content, optionally with your face from an uploaded photo, alongside 10 title suggestions and a description with chapter timestamps. The output is exported as a JPG under 2MB so it uploads without resizing.
Common questions
- What is the YouTube thumbnail resolution?
- 1280 by 720 pixels at 16:9. The minimum width is 640 pixels, but 1280 by 720 is what displays sharply.
- What file size limit does YouTube have for thumbnails?
- 2MB. A JPG at 1280 by 720 is normally well under that; a PNG often is not.
- Can I use a PNG thumbnail on YouTube?
- Yes, PNG is accepted, along with JPG, GIF and BMP, as long as the file is under 2MB.
Sources
- YouTube Help, "Add video thumbnails" (support.google.com), checked 2026-08-26.