What this checks
Checks the 16:9 thumbnail shape, recommended resolution, file type, upload size, and whether the image should stay readable in small mobile previews.
ImageCompat
Check your YouTube thumbnail before you upload
Check the size, shape, file type, transparency, safe area, and mobile crop before you upload.
Opens with YouTube thumbnail
Result
Ready when your image is.
Add an image to see whether it is ready to upload.
Preview
YouTube thumbnail
Add an image to see the guidance area and approximate crop.
White frame: safer areaTeal frame: approximate crop view
Guidance area: keep important content inside the white frame when possible.
Small-screen readability: Tiny text and edge details lose impact in mobile feeds.
Mobile framing
Add an image to see the mobile crop.
This is a static example. The checker above uses your actual image to show the personalized preview before upload.
Common problems
YouTube thumbnails often fail by being too large, the wrong shape, or hard to read when they shrink in search, home, or suggested video cards.
What the preview means
The preview shows a practical composition area so faces, titles, and key objects stay visible after YouTube scales the thumbnail down. It is not an official YouTube boundary.
Good to know
YouTube currently recommends 3840 x 2160. Mobile thumbnail uploads have a lower file-size limit than desktop uploads.