Three sourcing platforms, three sets of B2B marketplace image requirements — and the gap between them is smaller than the gap between a photo that gets inquiries and one that gets scrolled past. Alibaba.com publishes hard numbers. Made-in-China.com and Global Sources hide theirs inside the supplier upload panel. But line them up side by side and the surprising conclusion is this: the technical floor barely matters, because all three set it low, and none of them enforce the one thing that actually decides whether a buyer messages you.
This is the spec sheet for suppliers who list on more than one platform and are tired of guessing which rule applies where.
B2B Marketplace Image Requirements at a Glance
Here is what each platform enforces, current for 2026. Where a platform doesn't publish a number, that's noted plainly — a "confirm in your panel" is not the same as a rule you can ignore.
| Requirement | Alibaba.com | Made-in-China.com | Global Sources |
|---|---|---|---|
| Minimum resolution | 350 × 350 px (below this, upload fails) | Not published; set in supplier upload panel | Not published; set in supplier upload panel |
| Practical resolution | 1000–2000 px for zoom | 900 × 900 px floor (GS1 standard) | ≥ 1000 × 1000 px |
| Aspect ratio | 1:1 to 1:1.3 (enforced) | Not fixed publicly — shoot 1:1 | Not fixed publicly — shoot 1:1 |
| Max file size | 3 MB | Panel-set; keep a few MB | ~10 MB commonly cited; confirm in panel |
| Formats | JPG, PNG | JPG, PNG (GS1 also allows TIFF, GIF) | JPG, PNG |
| Background | Not mandated; white is field practice | Not mandated; white/transparent (GS1) | Not mandated; white is field practice |
| Main image slots | 6 (plus video) | Multiple; confirm in panel | Multiple; confirm in panel |
Read the table top to bottom and one pattern jumps out. Only Alibaba.com attaches public pixel numbers to its rules, and even those are low — 350 × 350 was a reasonable minimum a decade ago and is a thumbnail today. Made-in-China and Global Sources keep the exact ceilings inside the upload panel, where they can change without notice. So the "requirements" you can actually rely on across all three are format (JPG or PNG), a low pixel floor, and a file-size cap generous enough that you'll never hit it if you export sensibly.
That's the whole technical story. It fits on an index card. Which raises the real question.
The Rule That Actually Wins Orders Isn't in the Table
None of these platforms require your image to answer the buyer's first question: how big is this, and will it fit what I'm sourcing for?
A B2B marketplace image requirement is a technical gate — resolution, ratio, file size, format — that a sourcing platform checks before it publishes your photo. Passing that gate gets you listed. It does nothing to get you inquired. The buyer building a shortlist across forty near-identical listings is not comparing your pixel count to a competitor's; they're scanning for the one image that already told them the dimension, the tolerance, the packing size — so they don't have to message five suppliers to ask.
The pixel floor only decides whether your image uploads. The dimension on the image decides whether the buyer inquires. That's the line that separates a photo set buyers act on from one that technically complies and quietly loses.
This is why suppliers who obsess over hitting 4800 px and skip the spec layer keep losing to competitors with softer photos and clearer numbers. The Alibaba.com image requirements reward the same discipline in practice: fill every slot with distinct information, and put the size where the buyer's eye lands first.
Platform by Platform
Alibaba.com
The only platform of the three that publishes a numeric rule set. From the platform's Rules Center: images must be larger than 350 × 350 px, aspect ratio between 1:1 and 1:1.3, under 3 MB, in JPG or PNG. Below the floor, the image simply won't upload — with a famously unhelpful error that names none of the three failing conditions.
The silent killer is aspect ratio. A 4:3 photo straight off a camera is 1:1.33 — just outside the 1:1.3 ceiling — and fails to upload with no explanation. Crop square before you upload and the problem disappears for your whole catalog. Search-result tiles are square anyway, so a 1:1 image renders at full size while a taller one gets letterboxed smaller than a competitor's square shot in the same grid.
Made-in-China.com
Made-in-China.com sets its exact pixel and file-size limits inside your supplier account's upload panel, and those can change, so confirm them where you actually upload. For a target that both satisfies the platform and holds up to buyer scrutiny, follow the GS1 Product Image Specification — the global reference used across digital retail: minimum 900 × 900 px, JPG or PNG, white or transparent background, no watermarks, no upscaling. Hit that and you're safe on Made-in-China, Global Sources, and any retail channel you syndicate to later. The same logic runs through the Made-in-China.com product images that win inquiries: the platform rule is the floor; the spec on the image is the differentiator.
Global Sources
Global Sources doesn't publish public numeric image specs at all — its supplier help documents cover PDF catalogs and white papers, not photo pixel dimensions. Formats are JPG and PNG; a maximum file size around 10 MB is commonly cited but should be confirmed in your own supplier upload panel, since it's not in the public help center. In the absence of a published floor, use the same GS1-grade target: 1000 × 1000 px or larger, square, clean background. You will never be penalized for a cleaner, sharper image than the platform minimum requires.
The One Spec None of Them Mandate
Every platform above leaves the same slot empty: a dimensioned image. Not an engineering drawing — a buyer-facing photo with the real measurements marked on it. For furniture that's overall W × D × H plus seat height and internal clearance. For industrial parts it's critical dimensions, tolerances, and interfaces. For building materials it's format, thickness, and module.
The catch is accuracy. A labeled dimension that's off by two centimeters is worse than no label, because it becomes a dispute after the order ships. AI image generators can restyle a photo or swap a background, but they can't measure your product — AI-generated images can't measure dimensions, which is exactly why the spec slot still needs a real photo with numbers drawn from the real product. You can see the before/after difference in a real listing in this furniture size-label case study.
Pre-Upload Checklist (All Three Platforms)
- Export every image as JPG or PNG at 1000–2000 px, square (1:1)
- Keep each file well under the cap — JPG at 80–85% quality lands around 300–600 KB
- Confirm the exact pixel and file-size limits in each platform's upload panel (Made-in-China and Global Sources don't publish them)
- Main image: product only, clean white or light background, no burned-in promo text or phone numbers
- At least one image carries the real dimensions, drawn from the actual product
- Fill every available slot with distinct information — angles, scale, packing, variants — not duplicates
- Verify measurements against the physical product before publishing; a wrong number is a future dispute
FAQ
What are the image requirements for B2B marketplaces like Alibaba and Global Sources?
Alibaba.com publishes hard rules: minimum 350 × 350 px, aspect ratio 1:1 to 1:1.3, under 3 MB, JPG or PNG. Made-in-China.com and Global Sources set their exact limits inside the supplier upload panel rather than publishing them. Across all three, a safe target that always passes is 1000–2000 px, square, JPG or PNG, under a few megabytes.
Do B2B marketplaces require a white background?
No — none of Alibaba.com, Made-in-China.com, or Global Sources mandates a white background in its published rules. A white or light background on the main image is field practice, not policy: it renders cleanest in the search grid and matches what buyers expect from established suppliers. Context and application shots belong in the later slots.
What resolution should product images be for B2B listings?
The platform floors are low (350 × 350 on Alibaba), but buyers zoom to inspect welds, joints, and finish, so shoot 1000 × 1000 px or larger. Past roughly 2000 px you gain nothing at listing sizes and only spend your file-size budget on pixels no one renders.
Can I use AI-generated product images on B2B platforms?
You can use AI to clean or restyle a background, but an AI-generated product that differs from what ships violates every platform's accuracy expectation and invites disputes. AI tools also can't measure your product, so any image meant to show dimensions must be a real photo with real numbers.
What's the maximum image file size on these platforms?
Alibaba.com caps images at 3 MB. Made-in-China.com sets its cap in the upload panel. Global Sources is commonly cited at around 10 MB but doesn't publish it publicly — confirm in your supplier panel. Export JPGs at 80–85% quality and you'll clear all three caps with room to spare.