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Add an image or YouTube URL to begin
Thumbnail tester
YouTube Thumbnail Preview
See how your thumbnail’s text, subject, and hierarchy hold up in approximate desktop and mobile placements before you publish.
Creator check
✓ Uploads stay in your browserTest your thumbnail
Upload a thumbnailJPG, PNG, or WEBP · 10 MB max
Can you read the text?Is the subject clear?Does one idea lead?Does it work small?
Design at real scale
Why thumbnails change when they get smaller
A large editing canvas gives every element room. In a feed, the same image may be only a few hundred pixels wide. Small type loses definition, background detail merges, and a weak focal subject becomes hard to identify.
Test the visual idea, not just the finish. Strong contrast should separate the subject quickly, and one dominant element should guide the eye before secondary details.
Mobile-first checks
What to look for in the preview
01
Readable words
Use fewer, larger words. If you need to lean in, the text is too small.
02
Visible subject
Faces and products need enough scale and separation to register instantly.
03
Clear contrast
Check whether the focal element stays distinct against the background at feed size.
04
One hierarchy
Choose a single visual lead instead of making every element equally loud.
Keep working
Refine or find your thumbnail
Preview FAQ
About the thumbnail tester
Is this an exact copy of YouTube?
No. The placements are intentionally approximate and designed to help evaluate scale, hierarchy, and readability rather than reproduce YouTube's interface pixel-for-pixel.
Why does my thumbnail feel different on mobile?
The image appears smaller and competes with surrounding content. Fine text, weak contrast, and secondary details become harder to recognize.
Are uploaded previews private?
Yes. Uploaded image files are displayed locally in your browser and are not sent to TubeThumbnail.