Alt text describes the information an image contributes in its specific page context. For a product gallery, that is usually the product, a visible variant, a relevant detail, or the way the item is being used. Alt text is not a keyword list and it is not a second product description.
Google calls alt text the most important attribute for supplying additional image metadata. It supports people who cannot see the image and gives search systems context alongside computer vision and the page copy. The practical rule is simple: describe what matters in this image on this page.
Decide whether the image is informative, functional, or decorative
The role of the image determines the text alternative.
| Image role | Appropriate alt text |
|---|---|
| Informative product image | Describe the visible product and relevant distinguishing features |
| Image used as a link or control | Name the destination or action |
| Decorative image that adds no information | Use an empty value: alt="" |
| Infographic with essential data | Summarize the point and provide the full information in nearby HTML |
The W3C alt decision tree is more useful for edge cases than an arbitrary character limit. Google does not prescribe one ideal length. Stop when the text identifies the relevant information without repeating surrounding copy.
A practical writing pattern
Most catalog images need no more than three components:
Product + visible differentiator + view or action
Include brand, model, color, material, or included accessories when they distinguish what is visibly shown. Do not add shipping claims, prices, keyword variants, or properties that cannot be seen.
| Image type | Weak | Useful |
|---|---|---|
| Main image | Kettle product photo buy online |
Black stainless-steel kettle with wood handle, side view |
| Detail | Premium kettle detail |
Five-position temperature control on the black kettle |
| Variant | Green kettle |
K2 stainless-steel kettle in sage green |
| In use | Lifestyle kitchen image |
Sage-green kettle on a pale kitchen counter |
| Scale | Dimensions |
Kettle beside a 12-inch carafe for scale |
| Bundle | Coffee set deal |
Coffee filter set with holder, glass carafe, and 40 paper filters |
Longer is not automatically better. “Red leather backpack, front view” may be complete. Adjectives such as “premium,” “affordable,” and “perfect” do not describe the image.
Write for the actual gallery role
Main image
Name the product type and the details a shopper needs to identify the correct variant. Add the view when the gallery includes several angles.
Example: Navy roll-top hiking backpack, front view
Detail image
Describe the detail rather than restating the full product name.
Example: Padded shoulder strap on the navy hiking backpack
Lifestyle image
Mention the action or setting only when it changes the meaning. Do not infer a mood, profession, or demographic that the image does not establish.
Example: Person wearing the navy backpack on a woodland trail
Variant image
The named color or finish must agree with the product option. A fluent sentence is still wrong if automation assigns it to the wrong SKU.
Example: Trail 28 hiking backpack in sand beige
Infographic
Alt text cannot replace a complex chart. State the key point, then put dimensions, bundle contents, or comparison data into accessible page copy.
Example: Backpack dimensions: 20.5 inches high, 11.8 wide, and 7.1 deep
Leave these elements out
Avoid:
- the same keyword sequence on every gallery image;
- “image of” or “photo of” when the medium is irrelevant;
- invisible properties such as warranty, dispatch time, or discount;
- the complete product description on every image;
- file extensions, internal asset IDs, or generation prompts;
- colors, materials, and uses that are not actually visible;
- identical alt text for different angles or variants.
Google explicitly warns against keyword stuffing in alt attributes. This is also an accessibility failure: a screen reader should not announce ten near-identical blocks of search terms before a shopper reaches the product options.
Filenames, alt text, and captions are not interchangeable
| Element | Example | Job |
|---|---|---|
| Filename | trail-28-sand-front.jpg |
Stable, lightweight clue about the asset |
| Alt text | Trail 28 hiking backpack in sand beige, front view |
Text alternative for this use of the image |
| Caption | 28-liter version shown in Sand Beige. |
Visible editorial context for every reader |
Google recommends short descriptive filenames instead of names such as IMG00023.JPG or image1.jpg. Localized filenames can help when the assets are genuinely maintained by locale. Do not rename an indexed image merely for cosmetic SEO: changing the name changes the URL and requires a proper migration.
Scale the workflow without manufacturing text
Handwriting 10,000 descriptions is difficult to keep consistent. Blindly concatenating product fields creates a different problem: polished but incorrect descriptions. Use a controlled workflow instead.
- Define image roles: main, detail, in-use, variant, included items, and scale.
- Define permitted fields: product type, model, visible variant, view, action, and visible detail.
- Populate only evidenced fields: do not copy a PIM attribute that the image does not show.
- Create locale-specific drafts: do not translate terminology word by word without validation.
- Run automatic checks: flag missing values on informative images, duplicates, and variant contradictions.
- Review samples: every new category, template, and image role receives human review.
A useful export schema might contain:
| Field | Example |
|---|---|
product_type |
hiking backpack |
model |
Trail 28 |
visible_variant |
sand beige |
image_role |
detail |
visible_detail |
padded shoulder strap |
locale |
en-US |
Treat the generated sentence as a draft. Color, material, printed labels, and included accessories deserve a direct check against the image.
Ten-point review
- Would the text replace the image if it failed to load?
- Does it name the correct variant?
- Does it describe only visible, relevant information?
- Does it distinguish the main shot, detail, and use case?
- Does it avoid pointless repetition of nearby copy?
- Is it free of keyword lists and promotional language?
- Does a decorative image correctly use empty alt text?
- Does a linked image describe its destination or action?
- Are dimensions and bundle contents also available as HTML?
- Was the locale checked against real product terminology?
Alt text belongs to the wider asset workflow. The Google Shopping image requirements cover feed fields and AI provenance; the e-commerce product photography guide explains which image roles a product page needs.