YouTube will accept a surprising range of images and then scale them. That is how you get muddy type and stretched faces. This checker reads width, height, aspect, and file size from an image you select locally (nothing is uploaded to our server).
How to use this tool
- Choose your thumbnail file.
- Read dimension and ratio verdicts.
- If it is not 16:9, return to the artboard — do not stretch.
- Re-export if the file is huge; extra megabytes do not add sharpness on the CDN.
The spec that still matters
Target 1280×720, 16:9, under 2MB. PNG for graphics with hard edges; JPG for photos. Export from a 16:9 artboard, not a cropped screenshot of your timeline.
Professional notes
- Work at 1920×1080 if you like, then export a 1280×720 master for Studio.
- Keep a 2px inner margin from edges for compression artifacts.