Captions & subtitles

The best frame you shot.Plus the text that sells it.

Scans every frame for your strongest expressions, lays brand-kit text over the winners, and exports A/B variants in every platform size.

every
frame scanned for expressions
3
A/B variants per video
5
platform sizes exported
metadata_agent
AI captions
thisisthemomenteveryoneremembers
00:00 word-level sync · ±50 ms00:42

Frame selection that knows faces

A thumbnail lives or dies on the expression. The generator scores every frame for facial intensity, sharpness, and composition — then crops to put your face where the eye lands first.

  • Expression scoring across every frame, not sampled stills
  • Blur, blink, and mid-word mouth shapes rejected automatically
  • Rule-of-thirds crop with face emphasis
  • Contrast and saturation tuned for small-screen feeds
metadata_agent
Expression scoring across every frame, not sampled stills
Blur, blink, and mid-word mouth shapes rejected automatically
Rule-of-thirds crop with face emphasis

Text that survives the feed

Thumbnails get judged at 160 pixels wide. Overlays follow a three-word guideline, use your brand kit, and pass a mobile legibility check before export — if it can't be read on a phone in the sun, it doesn't ship.

  • Three-word overlay guidance drawn from your hook titles
  • Brand-kit fonts, colors, and stroke applied automatically
  • Mobile legibility check at feed size
  • Three A/B variants for YouTube's test-and-compare
metadata_agent
Three-word overlay guidance drawn from your hook titles
Brand-kit fonts, colors, and stroke applied automatically
Mobile legibility check at feed size

From input to finished render

  1. 1

    Input

    Tell the agent what you're starting from — a recording, a script, or a prompt.

  2. 2

    Format

    Pick the output shape: aspect ratio, file type, or platform target.

  3. 3

    Length

    Set duration or let the agent find the natural cut points for you.

  4. 4

    Features

    Layer in captions, music, b-roll, or any other agent in the same pass.

  5. 5

    Model

    The model router picks the right model for the job — quality where it matters, speed everywhere else.

Frequently asked

Ready to try Thumbnail Generator?

No credit card. 10 free AI minutes every month. The metadata agent is ready when you are.