You made one good square video, uploaded it, ticked every placement because that was the recommendation, and now it looks fine in the feed and cropped or letterboxed everywhere else. The creative is not the problem. The mismatch between one asset and a dozen very different surfaces is. Meta will happily deliver your ad into places its shape was never designed for, and the result quietly wastes impressions.
This guide covers what the formats are, where placements put them, and why a single creative rarely survives the trip. It stays concept-led on purpose. Exact dimensions, aspect ratios, file sizes and video lengths change often enough that any number written here would be wrong within a season, so every spec is deferred to Meta's own current sheet, linked below. Treat that sheet as the source of truth and this guide as the reason the sheet matters.
The formats, and what each is for
An ad format is the shape of the thing itself: how many assets, still or moving, and how the viewer moves through it.
Single image. One still. The fastest to make and the easiest to get wrong at feed size, because it has to carry the whole message in one glance. It is the workhorse for a clear offer or a strong single image, and it is often the honest starting point precisely because it forces you to say one thing.
Video. One moving asset. It earns more attention when the first moment earns it and wastes more budget when it does not, because most of the audience decides in the opening seconds whether to keep watching. The rule that governs it is the same one that governs organic video: the opening has to earn the next few seconds. That is worth its own read in how hooks work.
Carousel. Several cards the viewer swipes through, each with its own image or video and its own link. It suits a sequence (steps, a range of products, a before and after, a single story told across cards) and it gives the system several creatives to optimise between inside one ad.
Collection. A format built for browsing on mobile: a primary asset above a grid of products that opens into a fast-loading storefront experience. It is aimed at catalogue-style shopping rather than a single message, so it earns its place when you have a range to show, not one hero product.
Which format fits is a question about the message, not about which looks most impressive in a deck. A single clear offer does not need a carousel. A range of products is wasted as a single image. Meta maintains the current list of formats and what each supports in its Ads Guide. That is the page to check when a format's capabilities matter to your plan.
Placements: the same ad, very different rooms
A placement is where the ad appears. The feeds are one room. Stories and Reels are another. There are in-stream, search, and messaging surfaces, and there are surfaces across Facebook, Instagram and Meta's wider network. The important fact is that these rooms have different shapes and different viewer behaviour.
A feed placement is scrolled, usually with the sound off, in a roughly upright or square frame. A Stories or Reels placement is full-screen and vertical, often with sound, and it sits between pieces of content the viewer chose, so an ad that looks like an ad is dismissed faster. The same file cannot be ideal in both. A square video letterboxed into a full-screen vertical placement wastes most of the screen and reads as an afterthought, because it is one.
This is why "select all placements" and "upload one asset" pull against each other. You can do both, and Meta will crop and fit as best it can, but you are then trusting automatic cropping to do the framing you should have done. The current placements, their shapes, and where each appears are listed in Meta's placements documentation; read it as the map of rooms your one ad is being sent into.
Advantage+ placements, and when to let the system choose
Meta's default for placements is to let its system distribute your ad across all eligible surfaces and spend where it performs. The feature has carried the Advantage+ placements name in recent versions. The argument for it is real: the system can find cheap results in placements you would never have picked, and restricting placements by hand can raise your cost by starving the optimiser of options.
The catch is the one above. Broad placements only work well when your creative is actually built for the placements it lands in. Letting the system distribute a single feed-shaped asset everywhere gives it reach into rooms your creative does not fit. The two decisions are linked: broad placements plus placement-appropriate assets is a strong default; broad placements plus one asset is how budget leaks. Because Meta has renamed and reshaped this control before, confirm what it is called and how it behaves today in Meta's current documentation rather than assuming last year's behaviour.
The practical middle path is to provide the system with assets cut for the main shapes (an upright or square version for feeds, a full-screen vertical version for Stories and Reels) and then let broad placements distribute them. Meta supports supplying placement-specific assets within a single ad for exactly this reason; the current way to do it, and which placements accept customised media, is in its documentation.
Specs: defer, always
The temptation is to memorise the numbers. Resist it. Aspect ratios, safe zones, maximum file sizes, video length limits and text recommendations are all things Meta tunes, and a spec you learned last year is a trap this year. The durable skill is not knowing the current 16:9-or-9:16 answer. It is knowing to open Meta's Ads Guide every time you brief a new asset and building to what it says that day.
Two things are safe to internalise because they are about human attention rather than platform settings. Design for sound-off in feeds, because most of the feed is watched silent: captions and legible on-screen text are not optional there. And design for the small frame, because an ad is judged at feed size on a phone, not at full size in your design tool. The same discipline that makes an organic thumbnail read at feed size applies to a paid still: if it does not survive being shrunk, it does not survive the feed.
Where Acumin fits
Making the assets is where Acumin's Studio is genuinely useful. Studio is a shipped surface for producing the creative itself (images, thumbnails and the on-canvas design work) so the "we should cut a vertical version for Reels" decision becomes an asset rather than a note in a document. It does not place the ad or manage the campaign; that is Ads Manager's job. Use Studio to build the placement-appropriate versions this guide argues for, then upload them into the ad. And before you fund any of it, the organic read on which ideas earned attention in the first place is the honest input to what is worth producing at ad scale.
Do this today
Open one running ad and check two things: which placements it is delivering to, and whether the asset was actually designed for each of them. If a single feed-shaped file is being distributed into Stories and Reels, you have found budget that is being spent on a shape that does not fit. Cut one vertical version of your best-performing asset, supply it for the full-screen placements, and let the rest run. That single recut is usually the highest-return creative change available to a campaign that already works.