Alt attribute on business website images: what to write, SEO, accessibility and mistakes that erode trust

The alt attribute on <img> is not an SEO hack or red tape: it is the text description of the image used by screen readers, search engines and visitors when the photo fails to load. On a business website, a well-written alt improves accessibility, reinforces product or service context, and avoids low-quality signals that Google and users read as neglect.

In October 2026, once you have tuned srcset and sizes, the picture element and weight with WebP and AVIF, it is time to review what each image says in words — and what should not be repeated.

What alt is and what problem it solves

alt (alternative text) describes the content or function of the image. If the image is purely decorative, alt can be empty (alt="") so screen readers skip it. If it conveys information — team photo, dashboard screenshot, process diagram, meaningful icon — alt must convey that without seeing the picture.

In B2B and retail, images often sell trust: facilities, certifications, product in use. Without alt, you lose low-vision visitors and chances to rank in image search and long-tail queries related to your sector.

SEO: what helps and what does not

Google uses alt as one signal among many to understand the image and page. It does not replace a strong title or useful body copy, but specific alt aligns image, headings and search intent.

• Helps — Describe what is shown and why it matters on the page («Support team reviewing uptime metrics on a data-centre monitor»).
• Does not help — Keyword lists («cheap web design SEO London») or repeating the H1 word for word.
• Page context — The same file may need different alt in a catalogue vs a case study if the message changes.

Combine alt with sensible filenames and, where relevant, image optimization without sacrificing visual quality.

Accessibility: practical WCAG-oriented rules

1. Informative images — Alt summarises essential information.
2. Functional images — Describe the action («Open menu», «Download catalogue PDF»), not the icon in the abstract.
3. Complex images — Short alt plus long description in nearby text or a dedicated section.
4. Decorative — alt="" and, where applicable, role="presentation" on decorative SVG.

How to write good alt in 30 seconds

[Main subject] + [action or context] + [distinctive detail if it adds value]

• Weak: alt="product"
• Strong: alt="Series X industrial pump installed on a production line with control panel visible"

Alt in heroes, galleries and CMS

On the hero, alt should match the main message without copying the headline verbatim. If you use fetchpriority on the LCP image, alt remains required for accessibility.

In project galleries, avoid «project 1, project 2». Name the client (with permission), type of work or outcome. In blog posts, inline images should extend the previous paragraph, not repeat it.

Common mistakes on corporate sites

• Same alt on every image — Typical of misconfigured CMS templates.
• Missing alt on linked icons — Screen readers only hear «link»; describe the destination.
• Important content only in CSS background — Use semantic HTML or aria-label on the block.
• Keyword stuffing — Hurts trust and quality signals.
• Forgetting img inside picture — Alt lives on the final img in picture.

Performance and lazy loading

Alt does not affect weight, but it shapes experience when the network fails or lazy loading delays the image: users see alternative text. Keep width and height consistent so layout does not break when alt appears in the reserved box.

Pre-publish checklist

1. Does every informative img have specific alt?
2. Do decorative images use alt=""?
3. Do image-buttons describe the action?
4. Is hero/LCP alt aligned with your value proposition?
5. Have ES/EN/CA translations followed the same rules, not literal filename translation?

Conclusion

Good alt is product copy in miniature: it clarifies, convinces and opens your content to more people and search contexts. On business sites, treating it as part of each image brief — alongside format, weight and decoding — avoids legal, brand and technical SEO rework.

Want us to review your catalogue, blog or CMS templates? At aatsoft we audit images, alternative text and performance in one actionable report.