Catch tiny text before it goes live, then make a clean 16:9 JPG for upload.
1. Add a thumbnail
Choose an image from your device. It stays in this browser preview; it is not uploaded.
- Image dimensions and ratio will appear here.
- The small preview is illustrative, not an exact YouTube screen.
2. Check it at small size
The thumbnail is reduced in a sample video-card layout so you can judge the big shapes and text at a glance.
A strong preview makes the subject and key words easy to pick out when reduced. This tool checks dimensions and shows a small-size view; it does not score design quality or predict views, clicks, or YouTube performance.
3. Resize and download
Choose A or B, fit it to a 16:9 video thumbnail, and export a JPG sized for YouTube. The tool tries to stay below your chosen file-size target.
Choose an image first, then click “Resize and prepare JPG.” The download button appears here when the JPG is ready. If the 2 MB target requires reducing the selected dimensions, the final dimensions will be shown before download; review the image for softness or crop changes.
Watch the short walkthrough
Want a quick look at how this works? The video below shows how to check a thumbnail at phone size, resize it, and download the finished JPG.
