YouTube Thumbnail Resizer

Crop any image to a 16:9 YouTube thumbnail: 4K 3840×2160 for desktop uploads or 1280×720 under 2 MB for the mobile app. Free and private.

  • Files stay on your device
  • Free, no sign-up
  • Updated

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How to use the YouTube Thumbnail Resizer

  1. Upload your image (ideally at least 1280 px wide).
  2. Drag and zoom to choose what stays inside the 16:9 frame.
  3. Download the 4K version for uploading from a computer, or the 1280×720 version for the YouTube mobile app.

YouTube recommends 16:9 custom thumbnails of 3840 × 2160 pixels (minimum width 640 px). Uploads from a computer can be up to 50 MB; from the mobile app the limit is 2 MB. This tool crops your image to 16:9 and saves both sizes within those limits.

YouTube thumbnail size

Recommended size3840 × 2160 px (4K)
Classic size1280 × 720 px
Aspect ratio16:9
Minimum width640 px
File size limit50 MB on desktop · 2 MB in the mobile app
Shorts9:16, minimum height 640 px

Thumbnail tips

  • Keep text large and short — most people see thumbnails small, on a phone.
  • Avoid important details in the bottom-right corner, where the video length is shown.
  • Use a close-up face or a single clear subject with strong contrast.
  • A 4K thumbnail only looks sharper if your source image is large — upscaling a small image adds no detail.

You need a verified YouTube account to upload custom thumbnails. Limits checked against YouTube Help, which changes from time to time.

Frequently asked questions

Is my photo uploaded anywhere?

No. Your photo is cropped and saved inside your browser and never leaves your device.

Which size should I download?

Uploading from a computer: the 4K 3840×2160 version. Uploading from the YouTube mobile app: the 1280×720 version, which is kept under the 2 MB mobile limit.

Why does my thumbnail look blurry?

Start from a large image. Zooming in a lot on a small image enlarges its pixels, which can’t add detail.

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