About ThumbRoasty

You upload a thumbnail, and an AI reviews it the way a scrolling viewer would. You get a score from 0 to 100, separate scores for visual hierarchy, readability, and clickability, a short roast in plain language, and a few specific fixes. There's no account and no watermark, and you get five free reviews a day.

Alongside the AI tool there are free utilities that run entirely in your browser: a thumbnail size checker and a thumbnail preview tool. Each one is explained on its own page: thumbnail rater and thumbnail checker.

The AI reviews use Google's Gemini models. Your image is sent to the model to generate the review and returned to your browser. It isn't saved in a database or shared. The size checker and preview tool never upload your image at all.

• It can't predict your click-through rate. Real results depend on your title, audience, and topic.
• It gives an AI opinion of the design. Treat it as a fast second opinion, not a verdict.
• It doesn't replace testing with real viewers. See our guide to A/B testing YouTube thumbnails.

The blog is written by the ThumbRoasty team for YouTube creators. When a guide states a YouTube rule, such as a size or file limit, we check it against YouTube's own help pages and say when we last did. Where the numbers vary or aren't public, such as click-through-rate benchmarks by niche, we say so instead of making up a figure. Where a guide covers policy or copyright, it is general information, not legal advice.

Found something out of date or wrong? Tell us on the support page and we'll fix it.

Questions, feedback, or corrections: use the support page. Pricing details are on the pricing page.