Resize
Prepare a YouTube thumbnail
A custom thumbnail has two constraints that actually bite: the shape has to be 16:9 or YouTube letterboxes it, and the file has to come in under the upload limit or it is rejected outright. This page does both in one step - crops to 16:9, scales to 1280 by 720, and compresses under the limit while keeping the quality as high as that allows. Where a number here comes from YouTube's own help pages the page says so; where it is consensus, it says that instead.
How to prepare a YouTube thumbnail
- Drop in the frame or artwork you want as a thumbnail.
- Check the 16:9 crop - this is the shape YouTube shows.
- Download it, already under the size limit.
Supported formats
This tool accepts JPG, PNG, WebP, GIF, BMP and AVIF files. Everything is decoded by your own browser, so the formats available depend on what your browser can open - which for HEIC in particular varies between Safari and other browsers.
Frequently asked questions
What size should a YouTube thumbnail be?
1280 by 720 is the standard, and the ratio matters more than the exact pixel count: 16:9 is what YouTube displays, and anything else gets letterboxed or cropped. Larger than 1280 across gains nothing visible, because the thumbnail is shown far smaller than that almost everywhere it appears - including at a couple of hundred pixels wide in a sidebar, which is worth remembering when choosing how much detail to put in it.
Why does my thumbnail get rejected for being too large?
YouTube caps the file size of a custom thumbnail, and a screenshot saved as PNG very easily goes past it - a 1280 by 720 PNG of a detailed frame can be several megabytes where the equivalent JPEG is a few hundred kilobytes. This page compresses to JPEG under the cap, searching for the highest quality that fits rather than picking a fixed setting and hoping.
Will compressing make my thumbnail look bad?
At the sizes a thumbnail is actually displayed, almost certainly not. The compression searches for the best quality that fits under the limit rather than applying a fixed one, and a thumbnail is shown at a fraction of its stored size in most places on YouTube. Large flat areas and text edges are where JPEG shows first, so if your thumbnail is mostly text on a solid background it is worth checking the preview.
Is my thumbnail uploaded to this site?
No. It is cropped, resized and compressed by your browser on your device, and a content security policy the browser enforces prevents this page from sending it anywhere. Nothing about the thumbnail leaves the tab before you upload it to YouTube yourself.
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