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ThumbnailGrab

Free • No signup • Runs in your browser

Thumbnail Resizer

Load a YouTube thumbnail or upload your own image, then resize it to common social, ad, and video dimensions — with JPG, PNG, or WebP export.

Load a thumbnail or upload an image to begin

Preset dimensions
Export format

Resizing happens entirely in your browser using the Canvas API — the image is never uploaded to our servers.

Thumbnail resizer FAQ

Does the resizer upload my image to a server?

No. Resizing happens entirely in your browser using the HTML Canvas API. Only a YouTube thumbnail sourced by URL is fetched from YouTube's own CDN — nothing is sent to our servers.

What's the difference between crop to fill and stretch to fit?

Crop to fill keeps proportions correct by cutting off the edges that don't fit the target size. Stretch to fit forces the image into the exact dimensions, which can distort it if the aspect ratio changes.

Which format should I export?

JPG for photographic thumbnails (smallest file size), PNG for graphics or text-heavy designs where you need lossless quality, and WebP for a modern format that balances both.