Product images and alt text in Shopify’s AI catalog

Product photos get most of a merchant’s attention, and most advice about AI shopping skips them, partly because little is known. Here is what Shopify has published about images in its catalog, and what it hasn’t.

What the catalog holds about an image

Shopify’s developer docs show how a product looks when an agent asks the catalog for it. Each product carries a media array, and each item in it has a type, a url and an alt_text. The example in the docs is an image of a coffee bag with the alt text “Bag of fair trade organic whole bean coffee.” The same structure appears in the results of search_catalog, lookup_catalog and get_product (Storefront Catalog docs).

So two things travel with your picture: the file’s address and the alt text you (or Shopify) attached to it. An agent that wants to show a shopper an image gets the first. An agent that wants to know what the image is of, without looking, has only the second.

What we don’t know

Nobody has shown that alt text changes which product an agent picks. Shopify’s page on optimizing products for AI lists images among the product details AI platforms consider, and gives no guidance on image quality or alt text (Optimizing your products for AI platforms). No agent publisher has said it ranks on alt text either.

That shapes how much effort this deserves. Alt text is worth writing because it’s accurate, accessible and already expected on a well-run store, not because it moves a ranking. Treat any claim that it does as unproven.

What Shopify does require and measure

The catalog requirement is short: “Your products must have a title and at least 1 product image” (Shopify Catalog requirements). A product with no image is left out. The full list of ways products drop out is in Shopify Catalog requirements: why products get left out.

Past that floor, the admin’s search preview under Sales channels > Agentic scores each product with a listing-quality meter that includes image count, along with description length, verified reviews, variants and store policies (Managing agentic storefronts). Shopify calls the preview “a directional signal, not an exact prediction,” so a full meter doesn’t promise anything about an AI answer. Still, a product with one blurry photo will show up there as a gap you can close.

How to write alt text that holds up

Shopify’s guidance on alt text is plain: keep it “brief and descriptive.” The limit is 512 characters, and “125 or less is recommended” (Add alt text to product media). Its stated purposes are showing text when an image can’t load and describing the image to shoppers who use assistive technology, with a possible SEO benefit.

Some habits that follow from that:

• Describe what the picture shows. “Grey cotton muslin blanket folded on a white shelf” is a description. “Best organic baby swaddle blanket for newborns” is a slogan.
• Leave out facts that aren’t visible. A certification, a material or an age range doesn’t appear in a photo, so alt text that asserts one is a new claim with your name on it.
• Give variants their own alt text. If each color has its own photo, say which color it is.
• Skip the keyword list. It reads badly aloud.

Where a claim can hide in a picture

The bigger risk is the reverse: a claim that appears only in an image. Badges like “GOTS certified,” “pediatrician recommended” or “BPA-free” on a lifestyle photo are visible to a shopper and often absent from your description. Our advice in How to write product descriptions for AI agents is the same: if a fact matters and is true, write it in the description too, and if it can’t be backed up, don’t print it on the image either.

Those claims carry weight. In our claim categories, certifications and endorsements each have their own, and both are the kind worth checking before a shopper relies on them.

Watch the suggested alt text

Shopify’s media editor “might suggest alt text for images where alt text isn’t already filled in,” and accepting a suggestion saves it to the file (Add alt text to product media). Suggestions are convenient. They’re also machine-written text attached to your product, so read each one for anything the picture can’t prove. If a suggestion calls a fabric “organic” because the photo looks earthy, that’s a claim you never made.

The same applies to bulk work. Shopify lets you upload alt text in a CSV, which is efficient and also an easy way to push an unreviewed batch to every product.

A short image check

1. Every product has at least one image, and the first one shows the actual product.
2. Alt text exists, describes only what’s visible, and stays near 125 characters.
3. No certification, age range, material or benefit appears only in an image.
4. Variant photos match their variant names.
5. Alt text you didn’t write has been read by someone who knows the product.

This fits into the wider review in A 30-minute product data audit for AI agents. For more step-by-step guides, see the how-to tag page.

Common questions

Does alt text help my products rank in ChatGPT or other AI channels?

There’s no published evidence that it does. Shopify documents that alt text is part of the catalog record and doesn’t say how channels use it. Write it for accessibility and accuracy.

Can AI agents read the text on my product photos?

Shopify’s docs don’t say. The catalog record carries the image’s address and alt text, and what an agent does with the picture itself depends on the agent. The safe assumption is that a claim shown only in an image may not reach the shopper’s answer, so put it in text too.

Does Hearsay check my images?

No. Hearsay’s method compares text claims: what Shopify’s catalog tells agents in its summary, top features, tech specs and selling points, against your description, tags, product details and product page (how we check). It’s most useful for catching the claims in what Shopify’s AI adds to your listings that you never wrote. The free scan reads 5 of your products.