YouTube thumbnail requirements
According to YouTube Help (checked 19 October 2026), a custom thumbnail should:
| Requirement | Official value |
|---|---|
| Recommended resolution | 3840 × 2160 for videos, 2160 × 3840 for Shorts |
| Minimum | 640 px wide for videos, 640 px tall for Shorts |
| Aspect ratio | 16:9 for videos, 9:16 for Shorts |
| File type | Image formats such as JPG or PNG |
| File size | 2 MB when uploading from mobile, 50 MB from a computer |
1280 × 720 is the long-standing size most creators still use: it meets the minimum comfortably, matches 16:9 and is easy to keep under 2 MB. If your source image is 3840 px wide or larger, choose the 3840 × 2160 preset to follow the current recommendation. Do not enlarge a small image to 3840; it adds bytes without adding detail.
How to make a thumbnail
- Drop a frame grab, a photo or a design export. The 1280 × 720 preset with Crop to fill is already selected.
- Check the framing on the preview. Faces and text near the edges may be cut off; if so, choose Fit inside to keep the whole image with edges.
- Pixdesk saves a JPG at 90% and lowers the quality only if needed to stay under 2 MB, the mobile upload limit.
- Download the file and upload it in YouTube Studio under Thumbnail.
JPG or PNG for thumbnails?
YouTube accepts both. JPG is the safe default for photos and frame grabs: a 1280 × 720 thumbnail is typically 100–300 KB at quality 90 (our sample came out at 187 KB at 92%). PNG keeps flat colors and big text razor sharp, but a detailed PNG at 3840 × 2160 can exceed 2 MB, so check the size in the list before uploading from your phone. YouTube also shows thumbnails small in search and on the home feed, so bold shapes and big text matter more than fine detail.
Everything happens inside this browser tab. Pixdesk reads your files with the browser’s own image decoder, redraws them on a canvas in a background worker and saves the new file with the browser’s encoder. There is no upload endpoint on pixdesk.cc, and the page makes no network request while it works. You can check that yourself in two minutes with your browser’s Network panel.
Frequently asked questions
What size should a YouTube thumbnail be?
YouTube recommends 3840 by 2160 pixels for videos and 2160 by 3840 for Shorts, with a minimum width of 640 pixels. 1280 by 720 is a widely used 16:9 size that meets the rules and keeps files small.
What is the maximum file size for a YouTube thumbnail?
2 MB when you upload from the mobile app and 50 MB from a computer, according to YouTube Help. Pixdesk keeps thumbnails under 2 MB by default so they work in both places.
What aspect ratio do YouTube thumbnails use?
16:9 for regular videos and 9:16 for Shorts. Pixdesk crops from the center to the chosen shape, or fits the whole image inside with edges.
Should I use JPG or PNG?
JPG for photos and frame grabs because it is small and accepted everywhere. PNG for flat graphics with large text, as long as the file stays under the size limit.
Can I make a 3840 by 2160 thumbnail from a smaller image?
You can, but enlarging cannot add detail, so the image may look soft. Pixdesk warns you when the output is bigger than the source.
Can I resize several thumbnails at once?
Yes. Drop up to 30 images, such as a series of episode covers, and download them together as a ZIP.
How do I add the thumbnail to my video?
In YouTube Studio open the video details, choose the thumbnail option and upload the file you downloaded. YouTube Help says custom thumbnails need a verified account.
Does Pixdesk upload my image?
No. The thumbnail is created in your browser and never sent to a server.
Sources
- YouTube Help: Add video thumbnails — 3840 × 2160 recommended, at least 640 px wide, 16:9, 2 MB on mobile and 50 MB on desktop
Sources checked on 19 October 2026.