ImageSocial graphicsIntermediateGenerates an image

YouTube thumbnail concept

A 16:9 thumbnail built for legibility at small sizes: one expressive subject, 2-4 words of exact text and a strong contrast hierarchy.

For: Performance marketers, Creative strategists, E-commerce marketers · Works with: OpenAI GPT Image, Google Gemini image generation (Nano Banana), Ideogram, Any image generator

Your prompt

Design a 16:9 YouTube thumbnail for a video titled "How I Cut My Ad Costs in Half" aimed at ecommerce store owners. Text to render exactly (and only this): "ADS 50% CHEAPER" in huge, heavy letters, placed left side, vertically centred, with a thin outline for contrast. Subject: a surprised illustrated character looking at a falling cost graph, large, expressive and instantly readable at 168 pixels wide, placed right side. Background: a flat bold yellow gradient, simple, high contrast against the subject, no clutter. Colour: yellow, black and white with a red accent; saturated, with the text and subject clearly separated from the background. Constraints: no logos, no small text, no real celebrity or public-figure likeness, no fake play buttons or UI.

Customize

The fields start with example values so you can see how the prompt works. Everything stays in your browser.

The real video title; it keeps the thumbnail honest.

Who clicks.

2-4 words, true to the video.

Where the words sit.

The central visual; prefer illustration or generic subjects.

Where the subject sits.

Simple background.

Colours.

Example of what to expect

Illustrative only. It describes the kind of result this prompt aims for; real output varies by tool, model and run.

A 16:9 thumbnail with heavy black 'ADS 50% CHEAPER' text on yellow at left and a surprised illustrated character beside a falling graph at right.

Expected format: One 16:9 image; test at small sizes next to competitors' thumbnails.

How to use it

  1. Shrink to roughly 168px wide to test readability.
  2. Make sure the thumbnail promise matches the video.
  3. A/B test thumbnails with YouTube's built-in tools where available.

Limitations

  • Misleading thumbnails violate platform policy and hurt trust; the text must reflect the video.
  • Do not use real people's likenesses without permission.

Platform notes

OpenAI GPT Image

Official docs read · checked 2026-10-11

Aspect ratio is set with the size parameter, not in prose. Use medium or high quality for text and fine detail. Quote the literal text and describe typography as constraints; OpenAI and Google both document this pattern. Always proofread the result.

General notes on OpenAI GPT Image
  • OpenAI's guide covers gpt-image-2 (recommended), gpt-image-1.5, gpt-image-1 and gpt-image-1-mini.
  • Aspect ratio is set through the size parameter, not in prose. Quality is low, medium or high; medium or high is advised for small or dense text.
  • Put literal text in quotation marks, and when editing say what must stay unchanged.

Google Gemini image generation (Nano Banana)

Official docs read · checked 2026-10-11

Quote the literal text and describe typography as constraints; OpenAI and Google both document this pattern. Always proofread the result.

General notes on Google Gemini image generation (Nano Banana)
  • Google's docs list several Nano Banana models (2.1, 2 Lite, 2, Pro) and recommend 2.1 for new projects as of the verification date.
  • Supported aspect ratios include 1:1, 4:5, 9:16, 16:9 and 21:9; sizes 1K, 2K and 4K. Up to 14 reference images per request.
  • All generated images carry a SynthID watermark.

Ideogram

Not verified: third-party guidance only · checked 2026-10-11

Commonly used for text layouts, but only third-party guidance was found; verify its current behaviour.

General notes on Ideogram
  • Known for text-in-image work. Third-party guides advise quoting the text and describing font style and layout. We could not find Ideogram's own prompting guide, so treat this as unverified.

Any image generator

Official docs read · checked 2026-10-11
General notes on Any image generator
  • Written as natural-language descriptions that the verified image models accept. Syntax for aspect ratio, quality and negative prompts differs by tool, so set those in your tool's own controls.

Source, license and attribution

Origin
Original by MarketerTools
Publisher
MarketerTools
License
Original work by MarketerTools, free to copy and use. Informed by the linked documentation; no third-party text is reproduced.
Platform assumptions checked
2026-10-11

Documentation and references behind this prompt

These informed the structure and the platform notes. A reference is not a license, and no third-party prompt text is copied here.

Spotted an attribution error, or are you a source owner with a request? Use the chat button at the bottom right and quote prompt ID img-025. We will correct or remove it.

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