Every click starts with the thumbnail. Make yours unskippable.
Drop in a thumbnail and get a CTR score with exact fixes — color pop, face presence, readability at feed size. Drop in any photo and get a ready-to-paste AI prompt that recreates it. Built for YouTubers and the designers who sell to them.
Try it right now. No signup.
Upload a thumbnail for a real, pixel-measured score, or any photo for a generation prompt. Analysis runs on-device — your image never leaves your phone or computer — and right now it is all free and unlimited.
Drag & drop your image here
JPG, PNG or WebP · or paste from clipboard (Ctrl+V)Or try a sample
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—Do these fixes first
Title ideas that match this thumbnail
Scored on-device from your actual pixels — palette, contrast, sharpness, face-region and text-zone signals. Want a deeper AI read (subject, expression, on-image text)? Paste a vision API key in assets/app.js — the THUMBAI_API block at the top — and the same upload goes to the AI instead.
Your generation prompt
Palette, lighting and mood above are measured from your actual pixels. Paste the prompt into Midjourney, Nano Banana, DALL·E or Stable Diffusion to recreate — or remix — the shot.
Why this thumbnail works
Four of the signals ThumbAI measures, shown on a real frame. No face, no focal point, no contrast — no click.
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An expression you can read at 2 cm
Wide eyes, open mouth, head turned toward the object. On a phone feed the face is the size of a fingernail — subtle expressions disappear.
One glowing hero object
A single subject with a light effect around it. The pointing hand builds a literal arrow from the face to the product — the eye follows it for free.
Two colors, maximum fight
Red and yellow sit opposite on the thumbnail battlefield: they stay separable even in peripheral vision while scrolling.
Dead space reserved for text
The empty left third is not wasted — it is where three huge words go. Busy backgrounds behind text kill readability and the click with it.
The cluttered desk
Twelve objects, zero focal point, one flat gray palette. Nothing for the eye to grab in the half-second a feed gives you. Run it in the Studio and watch the Color Pop and Face scores.
The glowing phone
One face, one object, two colors, and a pointing hand acting as an arrow. Every element spends its pixels on a single job: stopping the scroll.
Steal the look of any photo — legally, it's just a prompt
Found a thumbnail style you love? Upload the image and ThumbAI reverse-engineers a prompt you can paste into any image generator to recreate the lighting, palette and mood with your own subject.
What ThumbAI reads from this photo
Sixty seconds from upload to action list
Upload anything
A finished thumbnail, a rough draft, or any photo whose look you want to borrow. JPG, PNG or WebP — phone screenshots work too.
Get scored & explained
Six measurable signals become one CTR score — and every weak signal comes with the exact fix, not generic advice.
Fix, re-upload, compare
Apply the fixes, drop the new version in, and watch the score move before the video ever goes public.
For YouTubers
Stop guessing which of your three drafts wins. Score all three, ship the strongest, and keep the fix list for the next video.
MORE CLICKS / VIDEOFor thumbnail designers
Send prospects a free ThumbAI audit of their last thumbnail — score, flaws, fixes — then pitch the redesign. The report is your foot in the door.
AUDIT → PAID REDESIGNFor video editors
Add a thumbnail score + prompt pack to every edit delivery. Same clients, bigger invoice, one extra upload.
HIGHER PACKAGE PRICEIt's all free. Seriously.
For a limited launch period, ThumbAI is 100% free and unlimited - no plans, no caps, no card, no account. Paid plans may come later; while this offer is up, everything on this page is yours to use as much as you want.
- Unlimited thumbnail CTR scores
- Unlimited photo to prompt conversions
- Fix lists, title ideas & downloadable audit reports
- No signup - the Studio above just works
Straight answers
Is the score real, or made up?
Real — it is computed from your image, never invented. The Studio measures saturation, contrast spread, sharpness, the size and position of the face region, clean text space and clutter in your actual pixels, and turns those measurements into the score and the fix list. If you paste a vision API key into assets/app.js (the THUMBAI_API block at the very top), the same upload also gets a deep AI read — subject, expression and any text in the frame — and the results panel tells you which engine produced your numbers.
Which image generators accept the prompts?
All of them. Universal format works in Nano Banana, DALL·E and Firefly as-is; Midjourney format adds the aspect-ratio and style parameters Midjourney expects; Stable Diffusion format adds a negative prompt. Pick the format in the Studio before you copy.
Can I use ThumbAI to win design clients?
That is one of its main jobs. Run a prospect's latest thumbnail through the Studio, download the audit report, and send it with your redesign pitch — a scored, specific critique opens doors that “I make thumbnails” never will. Audits are free and unlimited right now, so run one for every prospect on your list.
Do my uploads get stored anywhere?
Not by this page. By default, analysis happens entirely in your browser and the image is gone when you close the tab. The one exception: if you connect your own vision API key in assets/app.js, the image is sent to that provider for the deep read, under their privacy policy — and the results panel says when the AI engine was the one that ran.
What makes a thumbnail score high?
The big ones, in roughly this order: a face or single focal subject readable at tiny size, two or three colors fighting at full saturation, dark–light contrast that survives a squint, a clean zone for three or fewer huge words, sharpness that holds up after YouTube's compression, and a frame clean enough that nothing competes for the half-second of attention. The Studio measures every one of them.