Alt text, written as the alt attribute on an image element, describes what an image contains for users who cannot see it. That primary purpose is accessibility, and it remains the most important reason to write it well. But because search engines cannot see images either, alt text also gives them the clearest textual description of visual content on your page. Handled properly, it improves image search visibility, reinforces page relevance, strengthens internal linking, and protects the user experience when images fail to load.

What Alt Text Actually Does

Screen readers announce alt text in place of the image, so a blind or low-vision user understands what is being conveyed. When an image fails to load due to a slow connection or broken path, browsers display the alt text instead. Search engines use it to interpret the subject of an image and its relationship to surrounding content. And when an image is wrapped in a link, alt text functions as that link's anchor text, passing context about the destination page.

That last point surprises many people. Image-only navigation, banner promotions, and product thumbnails are all links, and without alt text they pass no descriptive signal at all. Fixing image link alt attributes is one of the fastest internal linking improvements available on most ecommerce and portfolio sites.

How AAMAX.CO Can Help With On-Page Optimisation

We are AAMAX.CO, a full service digital marketing company providing Web Development, Digital Marketing and SEO Services worldwide. Image optimisation is a small part of on-page work that we handle systematically rather than sporadically, because at scale it genuinely moves numbers. When you hire us for SEO services, we audit every image across your templates and content, identify missing, duplicated, or keyword-stuffed alt attributes, write descriptive alternatives aligned to search intent, and combine that with file naming, compression, modern formats, responsive sizing, and image sitemap coverage. Accessibility compliance improves at the same time, which is a genuine business benefit beyond search.

How To Write Alt Text That Works

Describe the image accurately and concisely, in the context of the page it sits on. If the same photograph appears in an article about roofing repairs and a page about ladder safety, the useful description differs. Aim for a natural sentence fragment rather than a keyword list, typically under about 125 characters so screen readers do not truncate it awkwardly.

Include your target keyword only when it genuinely describes the image. Forcing a phrase into every alt attribute across a site is a recognisable spam pattern that adds nothing and harms the experience for assistive technology users. Avoid starting with phrases like image of or picture of, since the technology already announces that it is an image. Do not repeat the file name, and do not leave the attribute containing something like DSC underscore four digits.

When Alt Text Should Be Empty

Purely decorative images — background textures, spacer graphics, ornamental dividers — should carry an empty alt attribute rather than a description. An empty attribute tells assistive technology to skip the element, which is exactly right. Omitting the attribute entirely is different and worse, because some screen readers then read the file name aloud. Similarly, if the surrounding caption or paragraph already conveys the information, repeating it in alt text creates redundant announcements.

Alt Text Is Only Part Of Image SEO

Alt attributes work best alongside the rest of an image optimisation programme. Descriptive, hyphenated file names help before a crawler even reads the markup. Compression and next-generation formats reduce weight, improving the page experience metrics that influence rankings. Explicit width and height attributes prevent layout shift. Responsive source sets serve appropriately sized assets to different devices. Lazy loading below-the-fold imagery speeds up initial render, provided above-the-fold images are excluded so they are not delayed.

Captions and nearby text matter too. Search engines read the context surrounding an image to corroborate what the alt attribute claims. An image placed inside a relevant section with a clear heading and explanatory copy is far easier to interpret correctly than one dropped between unrelated paragraphs.

The Commercial Case For Image Search

Image results drive meaningful traffic in visual industries: interiors, fashion, food, travel, construction, manufacturing, and design. Product photography, project galleries, diagrams, and original charts can all attract discovery traffic that never appears in standard blue-link reporting. Original imagery also earns citations and links when other publishers reference your visuals, which supports authority as part of a wider digital marketing strategy.

Auditing Images At Scale

Manual review does not survive contact with a large site. Use a crawler to export every image URL together with its alt attribute, then triage: missing attributes on content images, identical alt text repeated across many images, alt text over-stuffed with keywords, and image links with no description. Prioritise templates first, because a single template fix can correct thousands of instances at once. Then work through high-traffic and high-intent pages.

Build the standard into your publishing workflow afterwards. Requiring alt text before publication prevents the backlog from reforming, and documenting the guidelines means contributors write useful descriptions rather than guessing.

Images In An AI Search World

Multimodal AI systems interpret images directly, but they still lean on surrounding text and alt attributes to establish context, attribution, and factual grounding. Clear descriptions increase the chance your visual assets are understood and credited correctly when content is summarised. Our GEO services account for this, treating descriptive metadata as part of preparing content for retrieval by both crawlers and generative engines.

Conclusion

Alt text improves SEO by making visual content legible to machines, strengthening topical relevance, supplying anchor text for image links, and unlocking image search visibility — all while making your site usable for people relying on assistive technology. It is cheap, fast, and unambiguously worthwhile.

If your site has thousands of images and no consistent standard, hire us. We will audit the whole inventory, fix it at template level, write descriptions that serve users and search engines, and fold image optimisation into a measurable programme of on-page improvement.