A product page shows eight photographs of a blue ceramic mug. An editor pastes “blue ceramic mug premium home gift” into every alt field and changes only the number. Every image now has text, yet a screen-reader user cannot tell which view shows the handle, which shows the base and which is merely a background texture. Search engines gain little useful context from the repetition either.
Alt text is a text alternative to an image. The first question is what the image does on this particular page, not how many search phrases can fit in a field. This guide uses one mug's hero image, details, lifestyle view and decorative art to show how AI can draft alternatives and how an editor should verify facts, page purpose and both language editions. It is written for ecommerce and content teams managing product catalogues.
Give each image a job
Open the actual page before working from a folder of files. Note where the image appears, its neighbouring text and whether it is a link or button. The W3C images tutorial distinguishes informative, decorative and functional images. Even the same file may need a different alternative when its role changes.
The mug's hero image and close-ups of its handle and glaze are informative: they convey appearance or buying details. A texture used only as a page background is decorative; when represented by an img element, it can have an empty alt attribute so assistive technology skips it. A shopping-cart icon used as a standalone button is functional; its accessible name should convey “Add to cart.” If the same words already appear beside the icon, an empty alternative for the icon avoids needless repetition.
Do not confuse alt="" with omitting the alt attribute entirely. The former deliberately marks decoration; the latter may cause software to announce a filename. Nor should uncertainty lead to empty alternatives on every product photograph. Buyers need information about colour, structure and differences between views.
Build a small image inventory
Record image_id, page URL, position, purpose, verified product facts, draft alternative and open questions. This fictional mug gives a concrete starting set:
- 01 Hero: front of a blue ceramic mug on white; draft “Blue ceramic mug viewed from the front with a round handle on the right.”
- 02 Handle detail: draft “Round handle where it joins the blue ceramic mug.”
- 03 Base mark: describe brand text only if it is legible and confirmed; never ask a model to guess letters.
- 04 Capacity view: describe 350 ml only if a readable scale or approved product record confirms it.
- 05 Desk scene: draft “Blue ceramic mug on a wooden desk beside an open book”; shorten if the book adds no useful context.
- 06 Multi-angle composite: draft “Front, side and base views of the same blue ceramic mug.”
- 07 Pure decoration: alt="".
- 08 Cart icon: if it alone forms a button, convey “Add to cart,” rather than “Cart icon.”
Eight images should not share one phrase. Different angles should communicate different information. If a view contributes nothing new, decide whether it is decorative or should leave the page rather than inventing a distinction.
Limit what AI is allowed to infer
Use an approved tool such as ChatGPT or Claude to draft from images and your inventory. If you cannot upload images in your work environment, supply descriptions that a person has already verified and ask AI to make them concise and distinct. It must not guess a colour from a SKU, ingredients from packaging or a product capability from a plausible scene.
You are editing an ecommerce product page. For each supplied image and its position, classify its purpose as informative, purely decorative or a standalone functional image. Use only the verified product facts supplied here. For informative images, write one concise alt describing newly visible information; for pure decoration return an empty string; for functional images describe the action. Do not stuff keywords, start with “image of,” infer dimensions, materials, origin or performance, or transcribe unreadable text. Output image_id, type, draft alt, evidence and items needing human confirmation. If the purpose is unclear, mark it for review.
The evidence column makes overreach visible. “Ceramic mug that keeps drinks warm for three hours” cannot be inferred from appearance and must be rejected. A visible handle position can be checked. Start with eight sample images before processing an entire catalogue.
Let context guide length and search terms
Avoid empty prefixes such as “image of product” or “high-resolution picture.” A product name can appear naturally when it helps identify the view, but repeating a full marketing title eight times makes listening tiring. Google's image SEO guidance recommends informative, contextual alt text and advises against keyword stuffing. It does not promise search rankings simply because an alt field was filled.
Try a simple test: without seeing the image, can someone understand what this view adds from the alt and surrounding copy? If adjacent text already says “Handle detail,” the alternative might add angle or construction rather than merely repeat it. If an image carries important product specifications absent from the page, include those in accessible visible copy too; do not hide them solely in alt.
Review language editions on their actual pages
A bilingual site may keep Chinese alt on an English page or mechanically translate terms such as glaze and capacity. First check that the English page uses the same image, colour variant and specifications. A hero image might read “Blue ceramic mug with a round handle on the right”; a composite might read “Front, side and base views of the blue ceramic mug.” If the image differs, write a new description for that version instead of translating an old field.
Keep the logic of empty decoration and action-focused functional images in each locale. If the Chinese cart button has visible text but the English layout is icon-only, the English icon still needs an accessible name. Translation of a string alone cannot solve a changed interface. Review the live layout with content, design and frontend colleagues.
Sample-check facts and rendered HTML
First compare drafts against source images and approved records: AI must not fabricate colour, count, lettering, material or size. Investigate mismatches between the photograph and live product data. Then load both language editions and verify that alt appears in the HTML, does not duplicate neighbouring copy, leaves decorative images empty and names icon-only actions.
Ask a colleague to read only the page text and alternatives and identify which of the eight views adds information. If they cannot, the writing is still too generic. For fast-changing catalogues, retain image_id, reviewer and last-check date; changing a product image should return its alt to review. A caption can become false as soon as the photograph changes.
AI speeds up drafting. The quality comes from choosing the image's role, checking visible facts and understanding the page context. Review one mug's eight images carefully and reuse the inventory for the next item; thousands of unreviewed alternatives will not serve customers as well.