GrumpToolsImage
The thumbnail is the single biggest lever on click-through rate. See yours at every size YouTube renders, and drop it into a realistic YouTube homepage next to today's actual trending videos, before the video goes live.
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Video mode shows the standard home and search card, the medium up-next card, and the small size; Shorts mode shows the shelf and the player.
The full-page preview inserts your thumbnail into a YouTube homepage populated with today's real trending videos, the honest test of whether yours stands out.
Add your title, channel name, and duration to judge the complete card the way a viewer sees it.
Flip the full-page preview between YouTube's dark and light themes.
The image never leaves your device. Free previews every day; paid plans remove the daily cap.
1280x720 is the recommended YouTube size. Pick Video or Shorts mode.
See how the title wraps and pairs with the image at each placement size.
Open the full homepage mockup and spot-check yours against today's trending videos.
1280x720 pixels (16:9), at least 640 pixels wide, under 2 MB, as PNG or JPG.
Thumbnails compete at small sizes next to other videos. Text that reads fine in an editor often becomes illegible at card size, and a preview catches that before the upload.
High contrast, one clear subject, large readable text (three to five words at most), and expressive faces consistently outperform busy designs.
No. The thumbnail checker runs entirely in your browser; the image never leaves your device.
Free plan: 5 uses per day. Pro and Premium raise or remove the limit.