A 1280×720 JPEG thumbnail
A 1280×720-pixel JPEG at roughly 300KB comfortably clears both the resolution requirement and the 2MB file-size ceiling.
YouTube thumbnail size checker
YouTube's custom thumbnail requirements in one place — dimensions, file size, formats, and who is actually allowed to upload one.
YouTube thumbnail specs
Recommended size
1280 × 720 px
Aspect ratio
16:9
Minimum width
640 px
Max file size
2MB
Accepted formats
JPG, GIF, PNG
Who can upload one
Verified channels only
How to size a YouTube thumbnail correctly
- Design at 1280×720 pixels. Build your thumbnail at YouTube’s recommended 1280×720-pixel canvas so it renders sharp across every device, from a phone to a TV.
- Keep the 16:9 aspect ratio. Stick to a 16:9 ratio, matching the video player itself, rather than a square or vertical crop that gets letterboxed in the thumbnail slot.
- Stay above the 640-pixel minimum. Never export narrower than 640 pixels wide, which is the smallest width YouTube accepts for a custom thumbnail upload.
- Export under 2MB. Compress the file to stay under YouTube’s 2MB ceiling for a thumbnail image — a full-resolution 1280×720 JPEG comfortably fits under that limit.
- Confirm channel verification first. Verify that the uploading channel has custom thumbnails enabled before you design one, since only verified channels can set a thumbnail other than an auto-generated frame.
Worked examples
A 4K 3840×2160 thumbnail
A 3840×2160-pixel thumbnail is still 16:9, so the aspect ratio is correct, but the file needs careful compression to land under YouTube’s published 2MB limit at that resolution.
A 400-pixel-wide export
A 400-pixel-wide image falls under YouTube’s 640-pixel minimum width and will be rejected rather than accepted as a valid custom thumbnail.
YouTube thumbnail size FAQ
- What is the correct YouTube thumbnail size?
- YouTube recommends 1280×720 pixels, a 16:9 aspect ratio, with a minimum width of 640 pixels for a custom thumbnail upload.
- What file formats does YouTube accept for thumbnails?
- YouTube accepts JPG, GIF and PNG image files for custom thumbnails, all under the platform’s published 2MB file-size limit.
- What is the maximum file size for a YouTube thumbnail?
- YouTube’s published limit for a custom thumbnail is 2MB, regardless of which of the accepted formats — JPG, GIF or PNG — you use.
- Can every YouTube channel upload a custom thumbnail?
- No — custom thumbnails require a verified channel. An unverified channel can only choose from the frames YouTube automatically generates from the uploaded video.
- What aspect ratio should a YouTube thumbnail use?
- A 16:9 aspect ratio, matching the video player itself. A different ratio gets padded or cropped in the thumbnail slot rather than filling it cleanly.
- Does a higher-resolution thumbnail help a video perform better?
- Resolution mainly affects sharpness on large screens like a smart TV; going well beyond 1280×720 does not itself improve click-through — clear, legible design at the recommended size matters more.
- Can SkedCast set a custom YouTube thumbnail automatically?
- Not yet — SkedCast’s composer does not set a custom thumbnail when scheduling a YouTube upload today, so you would set it directly in YouTube Studio after the video publishes.
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