How to prepare assets for Google responsive display ads

With most ads, someone designs the finished thing and the platform places it. A responsive display ad reverses that. You supply ingredients: images in two shapes, logos, several headlines and descriptions, and a business name. Google then builds an ad for each slot it serves into, whether that is a rectangle next to an article, a banner across the top of a page, a thin strip at the bottom of a phone screen, or a text ad that uses none of your images.

The upside is reach: one set of assets covers thousands of sites and apps in every size. The downside is that most disappointing display campaigns start with assets that were produced as though they were the final ad. The specifications below come from Google Ads Help and the Google Ads API documentation, as checked in September 2026.

What to hand over, with the numbers

• Landscape images, 1.91:1: 1200 by 628 is recommended, 600 by 314 is the minimum, and each file can be up to 5 MB.
• Square images, 1:1: 1200 by 1200 recommended, 300 by 300 minimum. Google's spec pages disagree on the recommended square (one says 600 by 600, the other 1200 by 1200), so supply the larger.
• Quantity: Google's spec page allows up to 15 landscape and 15 square images. Its best practice guide suggests 5 to 10 of each, plus vertical 9:16 images at 900 by 1600.
• Logos: up to 5 square logos at 1200 by 1200 (128 by 128 minimum) and up to 5 wide 4:1 logos at 1200 by 300 (512 by 128 minimum).
• Short headlines: up to 5, each no more than 30 characters.
• A long headline: one, up to 90 characters.
• Descriptions: up to 5, each up to 90 characters. One Google guide puts the limit at 80, so 80 is the safe length to write to.
• Business name: up to 25 characters.
• Video, if you have it: 16:9, 1:1 or 2:3.

Every piece has to stand on its own

Google recombines these assets for each impression. Any short headline can appear with any description, beside any image, under either logo. That means each line of copy must make sense alone and next to any of the others. A description written to follow one specific headline will, sooner or later, appear after a different one and read oddly.

The layouts Google tends to build

Google is open about the fact that it changes the size, appearance and format of these ads, and that one ad may show as an image banner on one site and as a text ad on another. It does not publish a template per size, and real layouts vary, but some arrangements come up often:

• 300 by 250 rectangle: usually a landscape image on top, with the logo, a headline, one line of description and a button below.
• 728 by 90 leaderboard: a square image or logo on the left, text in the centre, a button on the right.
• 320 by 50 phone banner: space for little beyond a logo, a short headline and a small round button.
• 300 by 600 half page: logo, landscape image, long headline, description and a full-width button, stacked.

These fall into two families. Native layouts are styled by the publisher, fonts and colours included, so the ad blends into the site. Non-native layouts are built by Google using the main and accent colours you choose, or colours Google chooses if flexible colour is on. Switching flexible colour off removes the native layouts, which limits where the ad can appear.

Keep the words out of the images

The most frequent mistake is supplying the landscape image as a finished banner, with headline, price and logo designed into it. Google recommends against this, and the reason is mechanical. It crops, shrinks and reuses images across every size, and places its own headline and logo alongside them. Text inside an image gets sliced at the edges, becomes unreadable in a phone banner, or appears twice, once in the picture and once in the ad.

Choose images that work as images: the product, the place, someone using it, with the subject close to the centre and space around it. Put the words in the text fields, where Google can size them for each slot. If you want a banner that looks exactly as designed, that is a different format: an uploaded image ad.

When you need a banner exactly as designed

An uploaded image ad appears exactly as it was designed, but only in slots that match its size. Google accepts GIF, JPG and PNG files up to 150 KB. Animation can run for up to 30 seconds and must be slower than 5 frames a second. The common sizes are 300 by 250, 336 by 280, 728 by 90, 300 by 600, 160 by 600, 970 by 250, 320 by 50 and 320 by 100, and there is a longer list of less common ones. Plenty of advertisers use both formats: a responsive ad for reach, and a few designed banners for the sizes they care most about.

HTML5 banners follow separate rules. Google's image ad rules allow files up to 600 KB, and only for accounts that are more than 90 days old with over 9,000 US dollars of lifetime spend. Google says HTML5 support in Demand Gen is due in late 2026.

Display campaigns are moving into Demand Gen

Where display is bought is changing. Since April 2025, image ads in Demand Gen campaigns have been able to run on the Google Display Network as well as YouTube, Discover and Gmail, with channel controls to choose between them. In June 2026 Google started rolling out a tool that moves standard Display campaigns into Demand Gen. Its stated plan is that new Display campaigns will eventually be created only in Demand Gen, remaining ones will be migrated automatically, and the change will be complete in 2027. Display-only campaigns are still possible there, and both responsive display ads and uploaded image ads are supported, though manual CPC bidding is not. None of this changes the asset rules above.

Headlines, buttons and your business name

Short headlines have a hard limit: Google Ads rejects a 31st character. Write them to be taken in at a glance in a small banner, and save the fuller version for the long headline. Check the business name as well. At 25 characters, a long legal name will not fit, and a trading name usually reads better regardless.

The call to action defaults to Automated, meaning Google picks it. You can choose your own from Google's list: Learn More, Shop Now, Sign Up, Book Now, Contact Us, Apply Now, Get Quote, Subscribe, Download, Install, Visit Site and See More. Order Now is not on it; Shop Now is the closest.

Each responsive ad gets an ad strength rating from Poor to Excellent, and Google says adding horizontal, square and vertical images improves it. Treat the rating as a measure of how many combinations Google has to work with rather than a prediction of results. A Poor rating usually just means too few assets.

Leave the top right corner clear

Display ads carry Google's AdChoices marker in the top right corner. It is a small blue triangle containing an i, roughly 19 by 15 pixels, which expands to show the word AdChoices when someone hovers over it. Clicking it opens Google's About this ad page. Next to it is a close control that lets people stop seeing the ad and give a reason. Since that corner is often covered, keep anything important out of it.

Before you approve the campaign

• Every image supplied in both landscape and square, with no text in it and the subject centred.
• Both logos, on a transparent or plain background, still legible when small.
• Five short headlines that each work alone, one long headline, and descriptions that do not rely on one another.
• UTM tags on the final URL, so display visits are not misread as direct traffic in your analytics.
• A preview of the ad in the common sizes before it goes live.

Our free ad mockup generator is a quick way to do that last check. It cannot predict every layout Google will pick, but it will show you a headline that overruns or an image that crops badly, which are the mistakes that cost the most.

If you would like help producing a display asset set that holds up in every size, ALXO's design team would be glad to hear what you are planning.