Product Image Alt Text: The SEO and Accessibility Field Most Sellers Skip

Most product pages have a hidden field that quietly shapes whether your images rank in Google, whether screen reader users can shop with you, and whether a broken image still tells a customer what they were about to see. That field is alt text, and on most stores it is either empty or crammed with keywords. Product image alt text is one of the few SEO and accessibility signals you fully control on your own site, yet it is the field sellers skip most.

This guide is about the alt text attribute itself, mainly on your own Shopify, WooCommerce, or custom store and in Google Images. It is not another hero-image spec post. If you want the visual side of that equation, strong photography is the other half of the pair, and our take on why AI shopping product images are the new ranking signal covers how image quality now feeds discovery. Here we focus on the words behind the image, why they matter, and how to write them without wasting the field on keyword stuffing.

What product image alt text actually does

Alt text is a short written description of an image that browsers and assistive technology read when the image itself cannot be seen. It does four concrete jobs at once, which is why leaving it blank costs more than people assume:

• Screen readers. The W3C Web Accessibility Initiative treats product photos as informative images, which need a short text alternative conveying the essential information the image presents. A blind shopper hears your alt text in place of the picture.
• Image SEO. Google's own Image SEO documentation calls alt text the most important attribute for giving search engines metadata about an image, since Google cannot truly see the picture.
• Broken-image fallback. When an image fails to load, the browser shows the alt text instead, so a shopper on a slow connection still knows a product was there.
• AI and visual search context. Alt text and nearby text give machine systems written signals about what the image shows, which matters more as visual search grows.

See the W3C guidance on informative images and Google's Image SEO best practices for the primary sources behind those roles.

How to write product image alt text that works

Good product image alt text describes the specific item and its most important attribute in plain language, the same information a sighted shopper gets from the photo. The Shopify Help Center frames it well: keep it descriptive and specific, and do not simply repeat the product title. A few practical rules:

• Name the product specifically. "Matte black stainless steel water bottle, 750ml, with carry loop" beats "water bottle" and beats "bottle bottle cheap discount best."
• Include one key attribute, not ten. Color, material, size, or use case is usually enough. Detail beyond that belongs in the description, not the alt field.
• Give each image its own alt text. A product with five angles needs five distinct descriptions, because each photo shows something different.
• Avoid keyword stuffing. Google's image documentation and Shopify both warn against it; it reads badly to screen reader users and adds no ranking benefit.
• Skip "image of" or "photo of." Assistive technology already announces that an image is present, so those words are wasted.

On length, there is a persistent myth of a hard limit. WCAG sets no character limit; the widely cited 125-character figure traces to older versions of the JAWS screen reader pausing around that point in line-by-line reading. Treat roughly 125 characters as a target that forces concision rather than a rule. Shopify's field accepts up to 512 characters but recommends staying well under that.

Decorative versus informative: when to leave alt text empty

Not every image needs a description, and knowing when to use an empty alt attribute is part of doing this well. The W3C publishes an alt decision tree that maps this out. In a product context:

• Informative product photos (the item, its angles, texture, scale) get real descriptive alt text.
• Purely decorative images (a background flourish, a divider graphic that carries no information) should use an empty alt="" so screen readers skip them instead of announcing clutter.
• Functional images used as buttons or links (an add-to-cart icon, a thumbnail that links elsewhere) should describe the action, not the picture.

Empty alt is a deliberate, valid choice, and it is different from a missing alt attribute. A missing attribute leaves screen readers to guess, often reading the file name aloud. That is one reason Google also recommends descriptive file names such as green-linen-cushion.jpg rather than IMG_0423.jpg.

Where marketplaces differ: Amazon versus your own store

The single biggest source of confusion is that alt text is a field you control on your own store but generally not on Amazon. On a self-hosted or hosted store, every image element has an alt attribute you can edit. On standard Amazon listing images, sellers do not get a user-facing alt text field the way they get a title or bullet points; Amazon governs those images through its image requirements instead. Practical implications:

• On your own store, alt text is low-hanging fruit for Google Images and accessibility, and it is entirely in your hands.
• On Amazon, put your descriptive effort into the fields you do control (title, bullets, A+ content) and meet the image spec, since there is no seller alt field to optimize.
• Feed-based surfaces like Google Shopping rely on your product feed and image quality rather than page alt text, which is why the way Google AI shopping ranks your Shopify feed, not your page is worth understanding separately.

In short, treat alt text as an own-store lever. It does not replace marketplace optimization; it wins the parts of the web that read HTML directly.

Adding alt text in Shopify and WooCommerce

Adding product image alt text takes seconds per image once you know where the field lives. In Shopify, the Help Center describes the path: from your admin go to Products, open the product, hover over an image in the Media section, click the edit (pencil) icon, enter your text in the Image alt text field, then Done and Save. In WooCommerce, alt text is set through the WordPress Media Library: open the image, and fill the Alt Text field in the attachment details. A few workflow notes:

• Do it at upload time. Writing alt text while you add each image is faster than auditing an empty catalog later.
• Audit existing products in batches. Large catalogs can use bulk tools or apps, but review a sample by hand so the output stays specific rather than templated.
• Do not auto-generate identical alt text for every variant. Templated strings like "{Product} product image" defeat the purpose.

Shopify's official walkthrough is the Adding alt text to media page if you want the exact steps.

How AI visual search is raising the stakes

Visual search is now a mainstream shopping behavior, which makes describing your images well more valuable than it was a few years ago. Google reports that Lens handles a very large volume of visual searches each month and connects results to its Shopping Graph of billions of products, letting shoppers point a camera and pull up price, reviews, and where to buy. While Google has not published that alt text is a direct ranking factor for Lens, the broader principle holds: systems that understand images lean on every written signal around them, and alt text is one of the clearest. Two honest takeaways:

• Alt text is not a magic AI-search lever, and anyone promising exact ranking gains from it is guessing. Treat it as sound hygiene that helps machines and people read your images.
• The image itself still does most of the work. A clear, well-lit, correctly specced photo is what visual search and shoppers latch onto first, which is where investing in AI product photography pays off.

The pattern that wins is the pair: strong images plus descriptive alt text. One without the other leaves value on the table. If you want the feed side of visual discovery, the Google Shopping image requirements and the 500 by 500 rule cover the technical baseline your images need to clear first.

Product Image Alt Text FAQ

Is product image alt text a Google ranking factor?

Google's Image SEO documentation calls alt text the most important attribute for describing an image to search, and it directly supports appearing in Google Images. It is best understood as a real image-SEO signal and an accessibility requirement, rather than a lever that moves overall page rankings on its own.

How long should product image alt text be?

There is no official character limit in WCAG. The common 125-character guideline comes from older screen reader behavior and works as a practical target because it forces you to be concise. Shopify allows up to 512 characters but recommends staying well under that.

Should I put keywords in alt text?

Describe the product naturally and let relevant terms appear because they genuinely fit, not because you forced them in. Both Google and Shopify warn against keyword stuffing. If your description reads awkwardly to a person, it is over-optimized.

Does alt text matter on Amazon?

Standard Amazon listing images do not give sellers an editable alt text field, so your effort there belongs in the title, bullets, A+ content, and meeting Amazon's image requirements. Alt text is mainly a lever for your own Shopify, WooCommerce, or custom store and for Google Images.

When should product image alt text be left empty?

Use an empty alt attribute (alt="") only for purely decorative images that carry no information, so screen readers skip them. Every informative product photo should have specific descriptive alt text. An empty alt is a deliberate choice and is different from a missing alt attribute.

Published by Aashirvad Kumar, founder of ListingRVA AI. Drafted with AI assistance; the rules, figures and claims are checked against the sources linked in this article before publishing.