Most Shopify merchants treat image alt text as an accessibility checkbox. Some skip it. A few fill it in with the product title repeated. Almost nobody treats it as the SEO field it actually is.

This is a mistake. Alt text is one of the highest-leverage fields in your entire catalog because it does two things at once. It helps your product images rank in Google Image Search, and it makes your store usable by blind and partially sighted shoppers. Two real outcomes from one piece of writing.

What alt text actually is

Alt text is the short description attached to every image in your store. Shopify exposes it on each product image as the “Alt text” field, inside the image’s edit dialog.

When a screen reader encounters an image, it reads the alt text out loud. When Google’s image crawler indexes an image, it uses the alt text (plus surrounding text and the image file name) to figure out what the image shows.

If the alt text is empty, the screen reader announces “image” with no detail, and Google has to guess what the image contains from context alone. Neither outcome is good.

The SEO half

Google Image Search is a real channel. For visual product categories (apparel, beauty, furniture, home goods, food), image search can drive 10–30% of organic traffic to a Shopify store. That number drops to near zero when alt text is missing or generic.

A few mechanics matter:

Specificity ranks better than repetition. Alt text that just repeats the product title (“Black Hoodie”) will not outrank a competitor whose alt text reads “Heavyweight black cotton hoodie with kangaroo pocket, worn by a model against a concrete wall.” Google’s image ranking algorithm rewards descriptive text that matches long-tail search queries.

File name and alt text together. Google reads both. An image saved as IMG_4827.jpg with no alt text is invisible. The same image saved as black-cotton-hoodie-front.jpg with descriptive alt text appears in image search results for “black cotton hoodie”.

Surrounding text helps. Alt text doesn’t work in isolation. The product title, description, and the URL slug all reinforce what Google thinks the image shows. When all four agree (URL, title, description, alt text), the image ranks. When they conflict or some are empty, ranking suffers.

The accessibility half

About 2.2 billion people worldwide live with some form of vision impairment. A smaller subset use screen readers (assistive software that reads webpages out loud), but that subset includes paying customers who will leave your store immediately if it doesn’t work.

Without alt text, a product page has gaps. The screen reader announces “image, image, image” between every paragraph. The shopper has no idea what the product looks like, what colors are shown in the photos, or what the visual context is. Even if the description is excellent, the page is unusable.

There’s a legal angle too. In the EU, the European Accessibility Act came into enforcement in June 2025. Shopify stores selling into the EU need WCAG 2.1 AA compliance, which requires non-decorative images to have meaningful alt text. In the US, ADA web accessibility lawsuits hit roughly 4,000 cases in 2023 alone. Most of those cases name missing alt text as one of the violations.

(We make a separate tool for the broader accessibility audit work, AccessFix. For pure product-image alt text generation, CatalogFix is enough.)

How to write alt text that works for both

The rule of thumb: write what a friend would say if they were describing the image to someone who can’t see it, in one sentence, and lead with the most search-relevant information.

Bad: IMG_4827 Bad: Hoodie Bad: Black Hoodie Okay: Black cotton hoodie Better: Black heavyweight cotton hoodie with kangaroo pocket and drawstring hood Best: Black heavyweight cotton hoodie with kangaroo pocket, worn by a male model against a concrete wall

The “best” version includes the product, the material, key features, and the visual context. That last part matters because shoppers searching image results often filter by visual style (“flat lay”, “on model”, “on white background”). Including that context wins more image search clicks.

A few things to avoid:

  • Skip the “Image of…” or “Picture of…” opener. Screen readers already announce “image” before reading the alt text, so you get “image, image of black hoodie”.
  • Keyword stuffing reads as spam to Google and as nonsense to a screen reader. Black hoodie cotton cheap quality men's clothing apparel is not alt text, it’s noise.
  • Decorative images (a divider line, a swirly background) shouldn’t have alt text at all. Mark them with an empty alt attribute (alt="") so screen readers skip them.

What about variants and multiple images per product?

A typical Shopify product has 3 to 6 images. Each one needs its own alt text. The shopper sees them as front, back, detail, lifestyle. A screen reader user needs that same context.

A practical pattern that scales:

  • Image 1 (hero): full product description in alt text. Black heavyweight cotton hoodie, front view, worn by male model.
  • Image 2 (back/side): same product, different angle. Same hoodie, back view showing the print across the shoulders.
  • Image 3 (detail): zoom on a feature. Close-up of the kangaroo pocket and ribbed cuff.
  • Image 4+ (lifestyle): full context. Hoodie worn outdoors with grey sweatpants and white sneakers.

Every image gets its own descriptive sentence. Together they paint the picture for someone who can’t see the photos. Apart, they give Google four distinct opportunities to rank for related searches.

The bulk problem

The reason most Shopify catalogs have empty alt text is that filling it in manually does not scale. A store with 200 products and 4 images per product needs 800 alt text entries. Three clicks each through the admin UI. Nobody does that on a Friday afternoon.

Two real options exist:

  1. Hire a writer to bulk-fill it. Real outcome, but expensive. Roughly $0.50 to $2 per image at agency rates.
  2. Generate it with AI vision. A model that can actually look at the image and describe what it sees. Faster, cheaper, and the quality is now reliably good for product photography.

The second option is what we built. CatalogFix sends each image to Claude’s vision model, gets back a descriptive sentence, and writes it to the Shopify alt text field. You review every result before publishing. A 200-product catalog closes the alt text gap in one afternoon. Install on the Shopify App Store.