How to write a prompt that gives you a banner you can actually run

By AdflowKit · October 12, 2026 · 6 min read

"A modern banner for my coffee shop" gives you a nice picture with nothing to click on. A prompt that produces a usable banner describes the ad first: who it's for, what's on offer and why someone should click now. Only after that does it describe what the picture looks like. Below are the six parts of a good prompt, three before-and-after rewrites, a template you can copy and a way to fix a scene without starting over.

Four reasons banner prompts fail

1. There's no offer. The model can't guess your discount or free trial, so the banner doesn't say anything in particular.
2. Too many messages. Fast delivery, organic beans, a loyalty app and 20% off won't fit in a 300×250 rectangle. Someone scrolling past will read about four words.
3. Text inside the image. Image models still misspell words, and text drawn into the image gets cut off when the banner is cropped to other sizes.
4. No empty space. If the scene is full from edge to edge, the headline ends up on top of the busiest part of the picture.

The six parts of a good banner prompt

The message: one idea, about 30 characters

On the average, five times as many people read the headline as read the body copy.

David Ogilvy, Confessions of an Advertising Man (1963)

On a banner it's even more extreme than in Ogilvy's print ads. Most people see the headline and the button, and nothing else. Keep the headline to about 30 characters. That's Google's limit for short headlines in responsive display ads, and it also fits on a 320×100 mobile banner. You can test other angles later as separate banners (see A/B testing ad creatives).

The scene: brief it like a photographer

Use a reference to name the visual choices you want: background color, product angle and space for text. Our creative banner design gallery shows five techniques you can describe in your own brief.

The scene is the only part of the prompt the image model needs. Describe the subject, the setting, the light and colors and, most importantly, the composition: where the subject is and where the empty space for text goes.

Before and after: three rewrites

To choose a message before writing the prompt, browse our Facebook ad examples with sample copy or Google Display banner examples. Each guide explains when to use the concept and what the landing page should show.

Coffee subscription

BeforeMake a cool banner for our coffee subscription, modern style, attractive.

AfterOffer: first box 50% off. Audience: people who work from home and brew coffee every morning. Message: fresh beans roasted this week, delivered to your door. CTA: Get 50% off. Scene: a ceramic mug and a kraft-paper coffee bag on a light oak kitchen counter, morning sun from a window on the left, steam rising, shallow depth of field. Subject on the right third, plain bright wall on the left for the headline. Warm, natural colors. No text, letters or logos in the image.

What changed: it has one offer, a scene that could be a real photo, and space for the text planned in advance.

B2B software free trial

BeforeBanner for our project management tool, show the features, AI, collaboration, integrations, security.

AfterOffer: 14-day free trial, no card. Audience: team leads at agencies with 10–50 people. Message: see every project's deadline on one screen. CTA: Start free trial. Scene: a laptop on a tidy desk in a bright modern office, screen turned slightly away so no interface is readable, a plant and a notebook nearby, soft daylight, cool blue-gray palette with one indigo accent. Laptop on the right, clean wall space on the left. No text, no UI screenshots, no logos.

What changed: four of the five features are gone. "No readable interface" stops the model from drawing a fake UI with random text on it.

Local dental clinic

BeforeDentist ad, smiling people, professional.

AfterOffer: free first check-up for new patients this month. Audience: families in the neighborhood. Message: Saturday appointments available. CTA: Book a visit. Scene: a bright, calm clinic reception with light wood and white surfaces, a vase of fresh flowers on the counter, soft natural light, no people. Counter on the right half, open bright space on the left. No dental tools, no close-ups of teeth, no text.

What changed: a friendly empty reception tells people it's a clinic. It avoids close-ups that put people off and imagery that's more likely to cause problems in health ad review.

A prompt template you can copy

Offer: [what they get, with a number if possible]
Audience: [who, and the situation they're in]
Message: [the single reason to click, ≤ 30 characters as a headline]
CTA: [verb + outcome, 2–3 words]
Scene: [subject], [setting], [light], [color palette].
Composition: [subject position], [where the empty space for text is].
Avoid: no text, letters or logos in the image; [anything off-brand].

Fix the scene instead of starting over

The first image is rarely perfect, but you don't need to throw it away. A short follow-up prompt that describes only the change usually works better than rewriting the whole brief. In the clip below, the background of a finished banner gets the follow-up "Add vibrant creator studio lighting". The headline, CTA and logo stay exactly where they were.

Good follow-up prompts change one thing: "make the room brighter", "replace the mug with a glass of cold brew", "move the laptop further right". In AdflowKit a background change like this generates a new variant for one credit. Changes to the headline, description, CTA, colors and logo position don't touch the image, and they're free.

Small follow-ups like these are also the cheapest way to refresh a banner that has been running for weeks. Our guide to ad creative fatigue explains how to tell when a banner is worn out and what to change first.

Even faster: start from your landing page

Your landing page already has the offer, the audience and the benefits. Paste its URL into AdflowKit and the studio turns the page into a brief with a headline, description and CTA. You can change any of it before you spend a credit. The prompt drives only the background scene. The text and your logo are added on top as real, editable text, so the "no text in the image" limit is built in.

Checklist before you generate

• The offer is specific and checkable.
• The prompt has one message, and the headline fits in about 30 characters.
• The CTA starts with a verb and says what happens next.
• The scene has one subject and leaves room for the text.
• The prompt says no text, letters or logos in the image.
• Brand colors are given as HEX codes (see keeping AI banners on brand).
• The message still works on a 320×100 mobile banner (see Google Display banner sizes).

FAQ

How long should an AI banner prompt be?

Usually 60 to 120 words. Shorter prompts leave out the offer or the layout. Much longer prompts tend to pack in several messages, and the model mixes them together.

Should I ask the AI to write the headline on the image?

No. Put the headline on top of the image as real text. Text drawn by the image model is often misspelled, can't be edited and gets cut off when the banner is cropped to other sizes.

Can I write the prompt in a language other than English?

In AdflowKit, yes. You can write the brief in any language, and banner copy works in Cyrillic, Greek, CJK and right-to-left scripts.