AI Alt Text: How Do You Describe Marketing Images?

To draft alt text with AI, supply the image, its surrounding website or email copy, and the purpose it serves. Ask for a concise description of the information or function that matters, then review the draft against the actual image before publishing. Decide whether the image needs a description at all before asking AI to write one.

What is alt text, and what should it describe?

Alt text is a text alternative that communicates an image’s relevant information or function when the image cannot be seen. It is not a place to squeeze in a sales pitch or a list of keywords.

The W3C Web Accessibility Initiative’s Images Tutorial explains that appropriate text alternatives depend on an image’s purpose and context. Use that principle as your starting point: what would someone miss if this image were unavailable?

For a hypothetical bakery website, a cake photograph might show the appearance of a product. On a decorating tutorial, a similar photograph might demonstrate how to pipe frosting. Describe the information needed for that particular use, rather than everything visible in the frame.

Treat AI as a drafting assistant. Keep responsibility for the final description with someone who can compare the image, the surrounding content, and the intended task.

Does every marketing image need descriptive alt text?

No. W3C WAI distinguishes informative images, decorative images, and images that perform a function, such as links or buttons.

Before drafting, classify the image:

• Informative: It communicates something relevant that needs a text alternative.
• Decorative: It adds visual styling without conveying information needed to understand or use the content.
• Functional: It acts as a control or link, so its text alternative should communicate the action or destination.
• Complex: It presents detailed information, such as a chart, that may need a fuller text explanation outside the alt attribute.

For decorative images implemented with an HTML img element, WAI recommends an empty alt attribute: alt="". An empty attribute is not the same as omitting the attribute.

Imagine a hypothetical email with a decorative wave beneath a complete heading. If the wave contributes no meaning, do not ask AI to turn it into a description. By contrast, an image-only link to a booking page needs an alternative that identifies its purpose, not merely its colors.

Use the WAI alt Decision Tree when the classification is unclear. Do not let an AI-generated label settle a context-dependent decision.

How do you draft AI alt text step by step?

1. Prepare the image and its context

Use an AI tool that accepts image input, and supply the exact image intended for publication. Check your organization’s policies before uploading confidential material or identifiable customer images.

Alongside the image, provide:

• The page or email’s purpose.
• The nearby heading, caption, and relevant copy.
• What the reader should learn from the image.
• Whether it is linked, and where the link goes.
• Verified product details needed to interpret it.

Do not provide only a filename and ask the tool to infer the picture. For help organizing the brief, see what to include in AI marketing prompts.

2. Ask for a purpose-based draft

Try this reusable prompt:

Draft alt text for the attached image in the context below. First, suggest whether it is informative, decorative, functional, or complex, and explain your reasoning separately. For informative images, describe the relevant information concisely. For functional images, describe the action or destination. Do not invent details, add promotional language, or insert SEO keywords. Identify uncertainties separately from the proposed alt text. Context: [insert surrounding copy, image purpose, and link details].

Keep the explanation separate from the text you will publish. If the tool cannot inspect the attachment, stop and provide a verified human description rather than accepting a guess.

3. Compare the draft with the actual image

Review every descriptive word. Check objects, colors, positioning, visible writing, and any claimed product features.

For a hypothetical shop, suppose the image shows an open navy backpack with a padded laptop compartment. A useful draft might be:

Navy backpack open to show its padded laptop compartment.

Reject a version such as “Premium waterproof backpack that keeps your laptop safe.” Unless separately verified, those claims go beyond the visible details. Even verified selling points should not replace the image’s relevant information.

Avoid guessing someone’s identity, disability, occupation, or emotional state. Include personal characteristics only when relevant and supported by the image or verified context.

4. Edit for purpose, not maximum detail

Read the proposed description alongside the surrounding copy. Remove background details that do not help the reader understand the image’s role.

In a hypothetical gardening email, “Hands pressing soil around a seedling in a pot” might explain a planting step. Describing the tablecloth, wall, and window would distract from that purpose unless those details matter to the instructions.

Do not automatically remove all overlap with nearby text, either. Ask whether the final combination communicates the essential meaning clearly without unnecessary repetition.

Use the same deliberate review approach described in checking AI-written marketing content before publishing.

5. Add the approved text and inspect the output

Place the approved wording in the image’s alt-text field, not just its caption or filename. For decorative images, confirm that your publishing setup produces the intended empty alternative.

Preview the published page or send a test email. Check that descriptions remain attached to the correct images after cropping, replacement, or layout changes. For linked images, check the destination as well as the wording.

Where possible, include screen-reader testing in your review. Do not treat a visually correct preview as the only check, or assume that adding alt text completes an accessibility review.

How should you handle text inside images?

WAI advises that text alternatives for images of text contain the same words presented in the image. Check the wording yourself rather than trusting AI transcription.

For a hypothetical announcement graphic reading “Spring open house — Saturday — Main Street showroom,” preserve the meaningful announcement text. Do not replace it with “Colorful event banner.” If essential wording already appears as nearby real text, assess whether the graphic adds anything else that needs an alternative.

For a dense infographic, provide the detailed information in accessible page text rather than forcing everything into a long alt attribute. Use the alt text to identify the graphic and, where appropriate, point readers toward its fuller explanation.

How can you make this a repeatable publishing habit?

Keep a simple review record: image, placement, purpose, draft, approved wording, and reviewer. Revisit the wording whenever the image or its context changes.

Keep alt text factual even when surrounding marketing copy is playful. Avoid keyword lists and vague phrases such as “amazing product image.” Google’s image SEO guidance recommends useful, contextual alt text and warns against keyword stuffing.

For broader learning, explore WMU Membership, a monthly membership with courses, live sessions, and community. Keep this workflow focused: supply context, draft carefully, and approve the description only after human review.

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Sources

• Google Search Central: Google image SEO best practices