Marketplace Product Images: Meet Every Channel's Spec
Written byLeon · Founder, CEO
A marketplace media specification is the set of technical, compositional and structural rules a channel applies to every image attached to a listing, and it is enforced at publication rather than negotiated afterwards. It matters because image rules are the requirement most often discovered after a catalogue has already been mapped: attributes are validated by the feed, whereas photography is validated by the channel, sometimes by a human reviewer days later. Treating imagery as a data field with its own specification, rather than as creative work that happens to be attached, is what keeps a launch on its planned date.
The pattern is recognisable. Product data is cleaned, categories are mapped, offers are priced, and the feed passes. Then a portion of the catalogue is held back because the main image carries a lifestyle background, because the product occupies too little of the frame, or because a size chart was submitted as a product image on a channel that treats size charts as a separate asset type. The catalogue was ready; the asset library was not.
What a marketplace media specification actually contains
A media specification is three separate rule sets that arrive in one document. Confusing them is why teams fix the wrong thing: an image can satisfy every technical constraint and still be refused on composition, and it can satisfy both and still be refused because it was submitted in the wrong slot.
Technical constraints
Technical constraints are the measurable properties of the file: minimum and maximum pixel dimensions, accepted aspect ratios, file format, colour profile, maximum file size and, on some channels, a minimum long-edge threshold below which the zoom viewer is disabled. These are the easiest rules to automate and the easiest to get wrong at scale, because a library assembled over several years rarely holds one consistent export preset.
Composition rules
Composition rules govern what the picture may show. The common requirements on generalist marketplaces are a pure white background on the primary image, the product filling a defined proportion of the frame, no props that are not included in the purchase, and no text, logos, watermarks, borders or promotional badges burned into the pixels. The prohibition on overlaid text catches established brands most often, because their own webshop photography frequently carries a discount flash or a certification mark that the channel reads as promotional content.
Set structure and image roles
Set structure is the rule set teams underestimate. Marketplaces do not accept an undifferentiated pile of images; they accept a main image plus a defined sequence of secondary roles, and some of those roles carry their own rules. A size chart, a dimensional diagram, a packaging shot and a lifestyle image are usually distinct asset types with distinct permissions, and a lifestyle photograph that is acceptable in position four may be refused in position one. Minimum and maximum image counts also differ, and a category with a high minimum will hold a listing back until the count is met.
Why images get rejected after the listing passes validation
Feed validation and media review are different gates running on different clocks. A feed validator checks that an image URL is present, reachable and of a permitted type, which it can do in seconds. Whether the image satisfies the composition rules is frequently assessed separately, sometimes by automated classification and sometimes by a reviewer, and that verdict can arrive well after the listing shows as accepted. A team that treats a green validation result as proof of launch readiness will discover the gap at the point where it is most expensive to close.
The second cause is source drift. Images are usually pulled from whichever system happened to hold them, which in most organisations means a mix of the webshop media library, a supplier portal and a shared drive. Each source applies its own conventions, and supplier-provided imagery in particular tends to carry the supplier's own branding. When a channel refuses those files the fix is not a re-export but a re-shoot or a formal request to the supplier, and both have lead times measured in weeks. The same root cause sits behind most of the problems described in our guide to why marketplace listings get rejected and how to repair the workflow.
Build one master asset, derive every channel variant
The workable model is a single master image per product view, held at the highest resolution and the most permissive crop the brand owns, from which every channel variant is derived. The master is never published directly. Each channel receives a derived file produced by a documented transformation: a crop to the required ratio, a resize to the required dimensions, a background treatment where one is mandated, and an export in the required format and colour profile.
This inverts the common approach, in which the webshop image is treated as the master and each marketplace variant is edited by hand. Deriving from a true master has two practical consequences. A channel that tightens its dimensions can be re-satisfied by re-running a transformation rather than by reopening the original photography. And a product that is re-shot updates every channel from one place, instead of leaving older variants live on the channels nobody remembered to revisit. The master should also be photographed with the strictest channel in mind, since shooting to the loosest requirement and cropping upward is not possible. This is the imagery equivalent of the source-of-truth discipline described in our work on catalogue governance that prevents SKU drift.
Where channel requirements diverge most
Divergence is not random. It tracks what each marketplace's buyers are deciding between, which is why a specification cannot be generalised across a portfolio and has to be read per channel.
A generalist marketplace optimises for comparison across thousands of competing offers, so it enforces the strictest primary-image discipline: isolated product, white background, a high minimum resolution to support zoom, and a hard prohibition on anything that would make one offer visually louder than another. Compliance here is close to binary. Amazon is the clearest example of this pattern. Learn how to start selling on Amazon with e-tailize.
A fashion channel optimises for a purchase decision made on fit, drape and styling, so it asks for on-model photography, a consistent set structure across a collection, and frequently a defined shot sequence such as front, back, detail and styled. The rules are less about isolation and more about consistency within the set, and a mixed library assembled from several seasons will fail on coherence rather than on pixels. Zalando illustrates this well. Learn how to start selling on Zalando with e-tailize.
A category specialist optimises for technical confidence, so it tends to require imagery that demonstrates the product in use, scale references, and explicit visual documentation of components or dimensions. Here the constraint is usually asset coverage rather than asset quality: the brand has attractive photography but no dimensional diagram. Decathlon is a useful example. Learn how to start selling on Decathlon with e-tailize.
The practical step before committing to a launch date is to read the media specification for each candidate channel and each category you intend to list in, and to record the requirements alongside the rest of that channel's rules. Our overview of available marketplace integrations is a reasonable starting point for assembling the candidate list.
Who owns the image set after launch
Media requirements change, and they change without notice to the seller. A channel that raises its minimum resolution to support a new zoom viewer will usually continue to serve existing listings while quietly suppressing the zoom feature, so the degradation is invisible in any report the seller reads. The only reliable protection is a named owner and a scheduled review rather than a reaction to a complaint.
Three things belong in that review. First, whether the master library still satisfies the strictest live channel, which determines whether re-shoots are needed. Second, whether any channel has changed its specification since the last check, which is a documentation read rather than a data query. Third, whether products added since launch were given the full derived set, because new SKUs are where coverage gaps reappear. Image completeness is one of the strongest levers on marketplace visibility, for the reasons set out in our analysis of how product data quality drives marketplace ranking.
A pre-launch image checklist
- A master file exists for every required view of every SKU in scope, at or above the strictest channel's resolution requirement.
- The primary image satisfies the background, framing and no-overlay rules of every channel the SKU will be listed on.
- No supplier logo, watermark, promotional badge or certification mark is burned into any image intended as a product image.
- Secondary images are assigned to the correct roles, with size charts, diagrams and packaging shots submitted as their own asset types.
- The image count for each SKU meets the minimum for its category on each channel, and does not exceed the maximum.
- Derived variants are produced by a documented, repeatable transformation rather than by manual editing.
- Every image URL in the feed is publicly reachable, stable, and not behind a redirect or an expiring token.
- A named owner holds the media specification for each live channel and reviews it on a schedule.
None of this removes the need to confirm requirements with the marketplace itself. Specifications differ by channel, by category and by country, they are revised without a seller-facing announcement, and the version in a third-party summary is often behind the version the review system is applying. The channel's own seller documentation is the authority; the checklist above is what makes reading it productive.
Frequently asked questions
- What is a marketplace media specification?
- It is the complete set of rules a channel applies to listing imagery, covering three distinct areas: technical constraints such as pixel dimensions, aspect ratio, file format and colour profile; composition rules such as background colour, how much of the frame the product must fill and the prohibition on overlaid text or logos; and set structure, meaning which image roles exist, how many images a category requires and which asset types are permitted in which position.
- Why do images get refused after a feed has already been accepted?
- Feed validation and media review are separate gates. The validator confirms that an image URL is present, reachable and of a permitted file type, which it does immediately. Whether the picture satisfies the composition rules is assessed separately, sometimes by automated classification and sometimes by a human reviewer, and that result can arrive days later. A green validation result confirms the data, not the photography.
- Can the same image be used on every marketplace?
- Rarely, and relying on it is a common cause of launch delay. Channels differ on background treatment, minimum resolution, permitted aspect ratios and whether on-model or in-use photography is required. The workable approach is one master file per product view, held at the highest resolution and most permissive crop the brand owns, with each channel variant derived from it by a documented transformation rather than edited by hand.
- Why is overlaid text such a common cause of rejection?
- Because established brands usually inherit it without noticing. Webshop photography routinely carries discount flashes, certification marks, feature callouts or supplier branding, all of which a marketplace reads as promotional content on what is meant to be a neutral product image. The rule applies to pixels burned into the file, so it cannot be satisfied by editing the description; the image itself has to be replaced.
- What should be photographed before a first marketplace launch?
- Shoot to the strictest channel in the candidate set rather than to the average, because resolution and framing can be reduced later but not recovered. That means a high-resolution capture with margin around the subject so any required crop remains possible, a clean isolated view suitable for a primary image, and the secondary views the strictest category demands, which frequently includes a scale reference or a dimensional diagram that brand photography does not normally produce.
- How do fashion channels differ from generalist marketplaces on imagery?
- A generalist marketplace enforces isolation, because its buyers are comparing many similar offers and no seller may appear visually louder than another. A fashion channel supports a decision made on fit, drape and styling, so it asks for on-model photography and a consistent shot sequence across a collection. The binding constraint shifts from per-image compliance to coherence across the set, which is where libraries assembled over several seasons tend to fail.
- Should supplier-provided images be used on marketplace listings?
- Only after they have been checked against the same specification as your own photography, and with the understanding that they are the hardest files to repair. Supplier imagery frequently carries the supplier's branding or a watermark, and the remedy is a formal request to the supplier or a re-shoot, both with lead times measured in weeks. Establishing image rights and format requirements in the supplier agreement is considerably cheaper than discovering the problem during onboarding.
- What happens when a marketplace changes its image requirements?
- Existing listings usually continue to serve, but a capability is quietly withdrawn: a listing below a raised resolution threshold typically keeps its images while losing the zoom viewer. Because nothing is refused and no error is raised, the change is invisible in seller reporting. This is why the media specification for each live channel needs a named owner and a scheduled documentation review rather than a reaction to a symptom.
- How many images does a marketplace listing need?
- It depends on the channel and the category, and both a minimum and a maximum usually apply. A category with a high minimum will hold a listing back until the count is met, which makes image coverage a launch dependency rather than a quality improvement. The count should be established per channel and per category before the launch date is fixed, and confirmed against the channel's own seller documentation.