How Meta fills a missing aspect ratio: padding, crops and AI

Meta's Help Center says that if you don't provide "all four aspect ratio variations", the system "helps fill the gaps using adjustment options such as padding, media expansion, cropping and additional AI-enabled features." You can turn off "padding, media expansion or any other adjustment for individual variations at any time", in a screen Meta calls the aspect ratios view. The AI-generated versions are, on that page, something you opt in to. The surest way to skip all of it is the advice Meta lists first: "Upload your own variations when possible."

The detail (which adjustment runs on which media, in which placement) sits on other pages, and the page Meta links for "these options" was unavailable as of October 22, 2026.

What does Meta do when an aspect ratio is missing?

It adjusts what you gave it. From Meta's Best practices for aspect ratios:

When you create an ad in Ads Manager, your media is automatically adjusted to fit more placements. If you'd like more precise control over how your creative appears, you can upload assets in specific aspect ratios.

The page's section on how adjustments work describes the screen where this happens:

When you create or edit an ad, you can use the aspect ratios view to review and manage every aspect-ratio variation your ad needs — square, vertical, portrait or horizontal — in one place. This view lets you preview each variation, opt in or out and make adjustments before publishing.

Four variations, then: square, vertical, portrait and horizontal. Meta does not map those names to exact ratios. Its list at the top of the same page labels 1.91:1 and 16:9 both "Horizontal", 1:1 "Square", and 4:5 and 9:16 both "Vertical". The safe reading is that you need a square, a 4:5, a 9:16 and one landscape shape to leave nothing for the system to fill.

The page's media-customization section adds a warning that matters more than it looks:

If you want a specific asset to deliver only to certain placements, use placement opt-outs in addition to cropping. Cropping alone won't restrict delivery.

So cropping an asset to 9:16 does not limit it to Stories and Reels. Only a placement opt-out does.

Which adjustment happens where?

Meta's About Advantage+ creative page is where Meta names the mechanisms per media type. Three of its enhancements do the reshaping, and a fourth moves media between placements:

For images, the expansion is generative. Meta's wording: when visual touch-ups "expands images to fit different aspect ratios, it auto-generates new pixels to fit the space so your images can look more natural across different ad placements."

For video, the entry is more specific, and it has two limits:

For expansion, the aspect ratio of your videos will automatically expand to fit a 9:16 or 4:5 aspect ratio by using AI to generate new pixels in each video frame. Expansion can transform up to the first 15 seconds of your video. For cropping, the feature will crop the video or add blurred padding to fit the placement.

Read the placement column with that in mind. Under video touch-ups, a horizontal or square video sent to Instagram Stories or Reels can only be cropped or padded with blur; the entry lists AI expansion for Facebook Feed and Facebook Reels only. And on a long video, the page says expansion covers the first 15 seconds. It does not say how the rest is handled.

Catalog ads have a separate page. How aspect ratios of product images may be adjusted says product images "may be automatically resized to either a 1:1 (square) or 4:5 (portrait) aspect ratio", for example by "zooming in on the product or adding white space around it." In a carousel they may be resized "to match the aspect ratio of the first image shown in the ad." Image touch-ups adds a manual choice: "Crop the image and add borders, expand the image space around your product, or zoom in on your product and trim to fit."

Padding and cropping are the two geometric options the resizing post works through: turn a square into 9:16 and you either cut 43.8% of its width or leave 43.8% of the frame empty. Expansion is different in kind. It fills that empty space with pixels that were never in your file.

Is the AI fill on by default?

Meta's two pages frame it differently, so check both.

The aspect-ratio page treats generative fill as a choice. Its tip reads: "If you want to try AI-generated variations, opt in to features that expand or recompose your media from the aspect ratios view. Preview the result before you publish."

The Advantage+ creative page, which lists visual and video touch-ups, says "Some enhancements may be turned on by default, but you can turn them off at any time." Which ones are on is decided per ad, and some can only be switched off in Advanced preview; the enhancements post covers where each toggle lives. If you don't want Meta to fill a reshaped frame with generated pixels, look for Visual touch-ups and Video touch-ups (and Image touch-ups for catalog ads) in both the Enhancements step and the Advantage+ creative tab of Advanced preview.

Why might a 9:16 ad show up in Feed?

Flexible media. Meta's About flexible media page says "instead of one media asset getting delivered to one placement, one media asset may be delivered to additional placements that are likely to improve performance", and gives the example: "a 9:16 image for Stories or Reels ads may be used for Feed placements." It "may be turned on by default", and the page opens with "This product or feature may not be available to you yet."

The same page says something about cropping that is easy to miss. For images, flexible media "uses technology to help detect when important information might be cropped out of your images, and will prevent these ads from being delivered." For video, it can't: "We aren't currently able to detect if objects or text have been cropped out of videos like we're able to for images."

Two more lines settle how it behaves. Meta's best practices for flexible media say it "won't be applied if you upload the same image to multiple placements and only use the crop feature to adjust the aspect ratio of your original image." And the toggle is moving: for most objectives, "flexible media is gradually moving to Advantage+ creative", where it appears as Flex media on the Enhancements screen. For the awareness objective, or any objective with calls as the conversion location, it stays on the Crop screen.

Meta also says what flexible media is not: "Flexible media is different from the flexible ad format." The flexible ad format "looks at multiple media assets uploaded for an ad and determines which ad format is most likely to help improve performance"; flexible media sends one asset to more placements.

What can you turn off?

Each of these is a separate switch:

1. Padding, expansion and cropping, per variation. In the aspect ratios view. Meta: "You can turn off padding, media expansion or any other adjustment for individual variations at any time."
2. Visual touch-ups and Video touch-ups, per ad. In Enhancements, and again in Advanced preview → Advantage+ creative.
3. Flex media, per ad. On the Crop screen or the Enhancements screen, depending on the objective, as above.
4. Catalog resizing. Meta's page: "If you don't want your product images to be resized, provide all images in the same aspect ratio (either 1:1 or 4:5)." For a single ad, image touch-ups settings "take priority over your catalog's default settings."
5. Delivery to a placement. Only a placement opt-out. Cropping won't do it.

Which aspect ratio does Meta recommend for each placement?

These are the cells marked "Recommended" on Meta's Aspect ratios supported by placements table. The table also marks other ratios as supported.

The best-practices page adds three that the table doesn't mark: "For in-stream video: Horizontal 16:9 is recommended" (see Facebook in-stream video), "Meta Audience Network placements: Vertical 9:16 is recommended" (the table disagrees for one of those placements; see below), and for carousels "1:1 or 4:5 aspect ratios are recommended for images" with "Square 1:1 and consistent ratios" for video. It also says to keep carousel product images in one ratio "to prevent automated adjustments."

One more case where Meta changes the shape for you, with no setting involved: "On the computer version of Facebook Feed, the video will be shown with a 1:1 aspect ratio, which may cause black bars to appear on either side of the video."

For how the ratio itself is worked out, see aspect ratio.

Three ratios Meta's pages disagree on

Instagram Feed images. The placement table marks 4:5 "Recommended for images". The best-practices page says "1:1 is recommended for single-image ads to be delivered to Instagram Feed." Both are live.

4:5 carousels. The best-practices page says "The 4:5 aspect ratio is only available for Advantage+ catalog ads that are created using the carousel format and with product images from your catalog." Meta's ads guide for Instagram carousels gives "4:5 for carousels containing only images. Currently, for carousels containing videos, only 1:1 is supported." It sets no catalog condition. Our Instagram carousel spec page follows the ads guide.

Audience Network. The best-practices page says "Meta Audience Network placements: Vertical 9:16 is recommended." The placement table ticks 9:16 for Audience Network native, banner and interstitial, but marks rewarded videos as supporting only 1.91:1 and 4:5.

The "auto-crop" and "stretch" claims

Two popular guides describe a simpler system than Meta documents.

Ads Uploader's "Meta Ads Aspect Ratios" guide (updated July 31, 2026) says: "Meta doesn't reject mismatched ratios - it auto-crops them." It also says Meta's upload flow "asks you to provide three creative versions: 1:1, 9:16, and 1.91:1." Meta's page refers to four variations and names padding, media expansion and cropping, plus "additional AI-enabled features", as ways of filling a gap. And for images under flexible media, Meta says the opposite of a blind crop: it blocks delivery where "important information might be cropped out."

Marpipe's guide to designing catalog ads for placements (July 8, 2025) says: "If you don't upload all three aspect ratios, Meta will stretch, crop, or center your default creative." Meta's pages on aspect ratios don't use the word stretch. Meta's catalog page describes "zooming in on the product or adding white space around it."

The page Meta links for detail (unavailable in October 2026)

Meta's best-practices page sends readers who want the detail to "learn more about these options and how to customize your ad creative". That link, to About multi-media ads and customizing your ad creative, showed "Sorry, this content isn't available right now" as of October 22, 2026. So did the page the older placement-customization articles point to for "the new workflow". The section on media customization also carries the banner "This feature may not be available to you at this time."

It is the same page Meta's flexible-format article links to, and it was already unavailable in September, as the dynamic creative post noted. If your Ads Manager shows controls that none of the pages above describe, they may be documented on the unavailable page.

Which ratios to upload, and what to switch off

1. Upload 4:5 and 9:16 at minimum. Between them they cover feed, Stories, Status and Reels. Add 1:1 for Marketplace and carousels, and a landscape shape if you run in-stream video or the right column. To see which placements a file fits before you upload it, drop it into the free ad size checker.
2. Open the aspect ratios view before publishing. Meta asks you to "review auto-applied padding, cropping and expansion" there.
3. Check Visual touch-ups and Video touch-ups (and Image touch-ups for catalogs) in both enhancement panels if you don't want the frame filled with generated pixels.
4. Turn off Flex media and use placement opt-outs if a vertical asset must stay out of Feed. Cropping alone won't keep it there.
5. Keep text and logos inside the safe zone. Any of these adjustments can move the edges of your frame; the Stories and Reels percentages are where to start.
6. For catalogs, use one ratio across every product image. Mixed ratios are what trigger the catalog resize; Image touch-ups is a separate switch.

Sources

• Best practices for aspect ratios — Meta Business Help Center (accessed October 22, 2026)
• Aspect ratios supported by placements in Meta Ads Manager — Meta Business Help Center (accessed October 22, 2026)
• About Advantage+ creative — Meta Business Help Center (accessed October 22, 2026)
• About flexible media in Meta Ads Manager — Meta Business Help Center (accessed October 22, 2026)
• Best practices for flexible media in Meta Ads Manager — Meta Business Help Center (accessed October 22, 2026)
• How aspect ratios of product images may be adjusted in your ads — Meta Business Help Center (accessed October 22, 2026)
• Meta Ads Guide: carousel ads on Instagram Feed — Meta (accessed October 22, 2026)
• About the flexible ad format — Meta Business Help Center (accessed October 22, 2026)
• About multi-media ads and customizing your ad creative — Meta Business Help Center

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Meta revises these pages without notice, and several carry a "may not be available to you" banner, so what you see in Ads Manager can differ.

Terrads makes the square, portrait and vertical versions of one ad, plus a 16:9 landscape for image ads, each composed for its own frame, so there is less for Meta to pad, crop or expand.