Image alt text for Shopify: the SEO and accessibility guide

Image alt text is the most under-used SEO field on Shopify product pages. Most stores either leave it blank or fill it with the product title verbatim. Both are wrong — the first kills accessibility, the second wastes a real ranking opportunity for Google Image Search and Google Lens.

This is the guide for writing product image alt text that does both jobs at once: serves screen reader users and gets your images found in visual search.

What alt text actually does

Every image in HTML has an alt attribute. Browsers, screen readers, and search engines all consume it differently:

• Screen readers read the alt text aloud to users who can't see the image. Without it, the screen reader either skips the image or reads the filename — which is often something useless like IMG_1248.jpg.
• Google Image Search uses alt text as one of its core ranking signals. The phrase you put in alt text is part of how Google decides whether your image shows up for someone searching "cream linen pillow cover."
• Google Lens (visual search) uses alt text to verify what its image-recognition model thinks an image shows. The pair confirms the result — if alt text and visual model agree, the image gets a confidence boost in results.
• Browsers fall back to alt text when the image fails to load — slow connections, broken URLs.

One field, four jobs. Skipping it costs all four.

The 8-12 word rule

Alt text wants to be specific but compact. The working band: 8 to 12 words.

• Under 5 words → not enough information for Google or a screen reader to do anything useful with
• Over 15 words → reads as awkward and unnatural to a screen reader user, and Google may discount the trailing words as keyword stuffing

8-12 words gives you enough room to mention the product, its key visual attributes, and color/material — without sounding like a search-engine attempt.

What to include

For product images on Shopify, the formula that works is: color + material + product type + key visual detail

What to leave out

• "Image of" or "Photo of" — screen readers already announce that it's an image. Starting alt text with "Image of…" is redundant.
• The brand name in every alt text — your brand is mentioned in the page title, description, and Product schema. Repeating it in alt text on 12 product images is noisy.
• Promotional language — "premium," "luxury," "must-have." Alt text describes the image, not the marketing positioning.
• Information not visible in the image — don't say "hypoallergenic" or "machine washable" in alt text. Those are description details, not visual ones.

Alt text for multiple images of the same product

Shopify products often have 4-8 images per product — front, back, detail, lifestyle, scale shot. Each image needs its own alt text. The mistake is repeating the same alt text across every image of the same product. Google sees that and treats the alt text as boilerplate to be ignored.

Vary the alt text per image:

• Front shot: "Cream linen pillow cover with hidden zipper, 18x18 inches"
• Detail shot: "Close-up of linen weave texture and zipper detail"
• Lifestyle shot: "Cream linen pillow on a charcoal sofa in modern living room"
• Scale shot: "Linen pillow shown next to a 12-inch ruler for scale"

Each is distinct, each describes what's actually visible, each surfaces different long-tail searches.

Where to set alt text in Shopify

In the admin: Product → Media → click an image → "Add alt text". There's a small text field. Fill it. Repeat for every image. It's tedious for one product and infeasible across 500.

This is why automation helps. The Shopify Admin GraphQL API supports image alt-text writeback via the productUpdateMedia mutation with MediaImage GIDs. Apps that generate copy with image alt-text as a first-class output (ShelfCopy among them) handle this writeback automatically.

Accessibility check before launch

Before you ship alt text changes across a whole catalog, do one quick check with a screen reader. On Mac: System Settings → Accessibility → VoiceOver → enable. On Windows: built-in Narrator. Navigate to a product page and listen to how the alt text reads. If it sounds awkward, robotic, or repetitive, you've optimized for Google at the expense of the human user. The rule of thumb is: read it out loud. If it would feel weird in a conversation, rewrite it.

How ShelfCopy handles this

ShelfCopy writes descriptive 8-12 word alt-text on every product image during generation. It uses what's available about the product (title, type, tags) to write image-specific alt-text per image and writes it back to Shopify via the Admin API automatically — no manual click-and-paste across the media library. Every alt-text generation appears in the diff preview, so you can audit accessibility and SEO simultaneously before anything publishes.