Thumbnail Resizer
Drop an image and pick a size. It's resized in your browser, so nothing is uploaded, and YouTube thumbnails stay under 2 MB.
Free, no sign-up. Your image never leaves this device.
Your resized image shows here.
Tips
- YouTube wants 1280×720, under 2 MB, as JPG or PNG.
- 'Fill' crops the edges; 'Fit' keeps everything and adds a blurred background.
- Keep faces and text away from the bottom-right corner, where YouTube shows the video length.