Input, output & limits
Resize image for YouTube thumbnail use without an account or an upload. Static JPG, PNG and WebP inputs only. Animated files are not supported.
Input limit: 25 MiB (26,214,400 bytes) and 40,000,000 decoded pixels. Output width and height: 1–4096 pixels each. These are this tool's enforced limits, not YouTube requirements or a guarantee for every device.
Boundary checks passed on September 16, 2026 in desktop Chrome 153: a 25 MiB padded JPG decoded and exported; a 40,000,000-pixel PNG decoded and exported; inputs just above those limits were rejected. A 4096 × 4096 output exported successfully; 4097-pixel width was rejected. These synthetic checks verify our chosen limits, not the maximum capacity of your device.
No daily usage limit. Files live only in this page's memory and are discarded on reload or close. Downloaded copies remain on your device.
Know what changes
Fit preserves the whole composition and adds your chosen background. Fill uses a centered crop. JPG always uses the chosen background behind transparent pixels; PNG preserves transparency within the image.
JPG quality is passed to the browser encoder from 0.10 to 1.00. PNG encoding is lossless, but resizing still changes pixels. Enlarging cannot recover missing detail. Browser encoders may produce different bytes and sizes. Output bytes are measured from the actual encoded file after each change.
Official thumbnail guidance
Checked September 16, 2026. YouTube Help states: “3840 x 2160 pixels for videos”; “Mobile: 2 MB for video thumbnails”; “Desktop: 50MB for video, Shorts, and podcast thumbnails.”
The default 1280 × 720 is this tool's preset, not a claim about YouTube's current recommended resolution. Choose custom dimensions when needed.
Read YouTube's official thumbnail guidance ↗
Questions, answered
Can I resize without cropping?
Choose Fit to retain the entire image with padding.
Does a higher JPG setting guarantee a better thumbnail?
No. It changes compression, not the source detail or design. Compare the preview and encoded size.
Can I resize multiple images?
Process one image at a time. There is no daily count limit.
Are my pictures stored?
No server upload or storage. This page keeps the current image in memory until you replace it or leave.