Alt Text and SEO: The Quick Win Most Websites Are Still Missing

Most SEO checklists cover the same ground. Title tags. Meta descriptions. Backlinks. Core Web Vitals. Page speed. Alt text, if it gets a mention at all, tends to appear as a footnote — something to add when you have time.

That's a mistake. And it's one that most of your competitors are still making, which is exactly what makes it worth paying attention to right now.

Alt text isn't glamorous, it doesn't require a content strategy, and you won't see it celebrated in SEO case studies. But done properly, it gives search engines something they genuinely need, and it opens up a traffic channel — image search — that many sites are leaving almost entirely untouched.

What Alt Text Actually Does

The alt attribute was created to describe images to users who can't see them — whether because they're using a screen reader, the image fails to load, or they're browsing a text-only version of a page. It's a straightforward accessibility feature.

But search engine crawlers also use alt text to understand what an image contains. Googlebot can do basic image recognition now, but it still leans heavily on alt text when deciding how to index and rank images. If your product photo has no alt text, Google is essentially guessing what it shows based on surrounding context. Sometimes it guesses right. Often it doesn't.

When you write alt text, you're filling in a gap that would otherwise be left to interpretation. That matters for two separate reasons: organic image search rankings, and the overall context signals you're sending to Google about what each page is about.

The Image Search Opportunity Most Brands Ignore

Google Images accounts for a meaningful share of all searches — some estimates put it at around 22% of total web searches. For certain categories, it's even higher. Someone looking for "navy blue linen trousers" or "small bathroom tile ideas" is very likely to start with image search, not text search.

If your images aren't indexed and ranked, you're not just missing clicks — you're missing the top of the funnel entirely. The user finds a competitor's image, clicks through to their product page or blog post, and is already in their ecosystem before your site has had any chance to be considered.

Getting into image search isn't complicated. It requires images that load quickly, descriptive file names (not IMG_4892.jpg), proper structured data where relevant, and — most importantly — alt text that actually describes what the image shows in plain, accurate language.

What Good Alt Text Looks Like

The best alt text is specific, accurate, and written for a human reader first. It doesn't stuff keywords in. It doesn't restate the page title. It describes the image.

Here are three examples that show the difference:

• Empty: alt="" — Google gets nothing. The image is invisible to search.
• Keyword-stuffed: alt="buy cheap trainers online UK trainers sale" — This used to be common practice. Google now treats it as a quality signal to penalise, not reward.
• Actually useful: alt="White low-top leather trainers with gum sole on a wooden floor" — Descriptive, accurate, naturally includes relevant terms without forcing them.

For informational content and blog images, the same principle applies. If you have a graph showing organic traffic growth over six months, don't write alt="SEO graph". Write alt="Line graph showing 140% organic traffic growth from January to June 2026". That's useful to a screen reader user, and it gives Google a clear signal about what the image contains.

E-Commerce: Where the Stakes Are Higher

For online retailers, poor alt text has a compounding effect. If you have 200 products each with three or four images, that's potentially 600–800 image assets generating almost no SEO value. Each missing alt attribute is a small lost opportunity, but collectively they add up to a significant gap in your site's authority and discoverability.

The product images that rank in Google Shopping and image search can drive purchase intent directly. A user who finds your product image in search and clicks through is often further along in the buying cycle than someone arriving from a blog post. They know what they want. Getting your images in front of them at that moment matters.

Good e-commerce alt text should include the product name, key descriptive attributes (colour, material, style), and any other details visible in the image that a potential buyer might search for. Keep it under 125 characters where possible — screen readers typically cut off beyond that.

Common Mistakes Worth Knowing

Beyond empty or stuffed alt text, there are a few patterns that come up repeatedly:

• Using "image of" or "photo of" at the start. Google knows it's an image. You don't need to say so. Jump straight into the description.
• Writing the same alt text for multiple images. If you have five product images showing different angles, each should have distinct alt text reflecting what that specific shot shows.
• Ignoring decorative images. Purely decorative images — dividers, background shapes, icons used for style — should have an empty alt attribute (alt=""). This tells screen readers to skip them and stops you diluting meaningful alt text with noise.
• Leaving CMS-generated filenames as alt text. Some platforms auto-fill alt text with the filename. Check that this isn't giving you thousands of instances of DSC00194 as your image description.

How to Audit What You Already Have

If you've never checked your site's alt text coverage, start with a crawl. Tools like Screaming Frog (free up to 500 URLs) will show you every image on your site along with its alt attribute. Filter for missing or empty alt text and you'll immediately see the scale of what needs addressing.

Prioritise pages that are already getting traffic first — product pages, blog posts, key landing pages. Adding alt text to pages nobody visits is lower value than fixing the pages where you already have something to build on.

For new content, build alt text into your publishing workflow. It takes maybe 30 seconds per image if you're doing it at upload time. Going back to fix it retroactively across a 500-page site takes considerably longer.

It's genuinely one of those SEO tasks that sounds too simple to matter, until you see sites that have done it consistently and compare their image search traffic to those that haven't. The gap is often larger than people expect.