Why Your Website Images Might Be Quietly Hurting Your Search Rankings

Most small business owners spend hours picking the right photos for their website and about thirty seconds naming the files. That gap matters more than it looks. Search engines cannot see a picture the way a person can. They read the words attached to it, and if those words are “IMG_4021.jpg” or nothing at all, the image is invisible to search, no matter how good it looks to a human visitor.

Key Takeaways

A search engine reads an image through its filename and its alt text, not the picture itself, so a file called “photo3.jpg” tells it nothing useful.
Alt text is a short written description of what is actually in the picture, originally built for screen readers, and it doubles as one of the clearest signals search engines have about an image.
Descriptive, hyphen-separated filenames written in plain words help both Google Images and regular search results understand and rank a page.
Image SEO is one of the few ranking factors a business owner can fix themselves in an afternoon, without touching code or hiring anyone.
Getting this right can bring in extra visitors through Google Images and voice search, on top of whatever ranking gains show up in normal results.

This is not a technical secret reserved for developers. It is closer to good housekeeping: a habit that costs a few extra seconds per image and pays off every time someone searches for something your photos could have answered. The rest of this guide walks through exactly what to change and why it works.

What a search engine actually sees when it looks at your image

Search engines crawl text, not pictures. When a crawler reaches an image, it has three main sources of information: the filename, the alt text, and any surrounding text on the page. Alt text, short for alternative text, is a written description added to the image’s HTML so that screen readers can describe the picture to visually impaired users, and so that a browser has something to show if the image fails to load.

Google’s own documentation on image SEO confirms that both the filename and the alt attribute feed directly into how an image gets understood and surfaced in results, alongside the text near it on the page (Google Search Central). If both are missing or meaningless, the image contributes nothing to the page’s relevance, even if it is the single most useful photo on the site.

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Filenames matter because they are often the first thing a search engine parses, before it even loads the image. “bakery-shopfront-walthamstow.jpg” tells a search engine (and a human glancing at a URL) exactly what it is looking at. “DSC00847.jpg” tells it nothing. The fix costs nothing and takes seconds: rename the file before you upload it, using lowercase words separated by hyphens, not underscores or spaces.

Alt text is not just for search engines

It is worth being honest about where alt text came from, because that history explains why it works so well for SEO too. Alt text was built for accessibility, specifically so that screen reader software could describe an image to someone who cannot see it. WebAIM, a long-standing accessibility resource, sets out clear guidance: alt text should describe the content and function of an image concisely, without repeating information already given in nearby text, and without stuffing in keywords that do not describe what is actually shown (WebAIM).

Good alt text describes what is in the picture, not what you wish the page ranked for.

That distinction trips a lot of business owners up. Writing “best plumber London emergency callout cheap” as alt text for a photo of a van is not alt text, it is keyword stuffing with a picture attached, and search engines are generally good at spotting the difference. Genuine alt text for that same image might read “a white plumbing van parked outside a terraced house in London.” It is specific, it is true, and it still contains useful, natural language a search engine can work with.

There is a second reason to get this right that has nothing to do with rankings. A meaningful proportion of visitors rely on screen readers or have images turned off to save data, and for them, blank or missing alt text means a gap in the page that makes no sense. Fixing image SEO and fixing accessibility are, in this one respect, the same job done once.

A simple routine for every image you upload

You do not need a checklist app or a plugin to get this right, just a habit you repeat every time you add a photo to the site.

Before uploading, rename the file to describe what is actually in it, in a few plain words, separated by hyphens: “handmade-ceramic-mug-blue-glaze.jpg” rather than the camera’s default name. Keep it short enough to read at a glance, not a full sentence crammed with dashes.

When you add the alt text field in your website editor or content management system, describe the picture as you would to someone on the phone who cannot see it. What is in the frame, and what is it doing there. Skip the phrase “image of” or “picture of,” because a screen reader already announces that it is reading alt text, so adding it again is redundant. Moz’s guide to image SEO makes a similar point: alt text works best when it reads like a natural, specific sentence rather than a list of keywords bolted together (Moz).

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If an image is purely decorative, a background pattern with no informational content, it is fine to leave the alt text empty rather than inventing a description for the sake of it. An empty alt attribute tells assistive technology to skip the image cleanly, which is a better outcome than a meaningless description that wastes a screen reader user’s time.

Why this is worth doing even on a small site

It is tempting to assume image SEO only matters for big retailers with thousands of product photos. In practice, it matters just as much, arguably more, for a small local business, because every extra route into search results counts when you are competing against sites with far bigger marketing budgets. Analysis from Ahrefs on image search behaviour notes that a meaningful share of all Google searches happen inside Google Images specifically, and that pages with well-optimised images tend to pick up additional visits through that channel on top of standard organic traffic (Ahrefs).

Image search is a second doorway into your site that most small businesses leave locked.

For a business that relies on visual proof of its work, a bakery, a tradesperson, a workshop, this second doorway is not a minor bonus. A well-named, well-described photo of finished work can surface in an image search for exactly the kind of query a prospective customer types when they are deciding who to hire.

This kind of unglamorous, page-by-page fix is exactly the sort of work an SEO specialist ends up doing during a proper site audit, alongside the bigger structural changes. Pomegranate, which offers SEO services humbly summarised on pomegranate.marketing, has run workshops covering practical search fundamentals with Enfield and Waltham Forest councils and the British Library’s Business & IP Centre, the kind of session where habits like this one tend to come up. It is not complicated work, it is just work that gets skipped because it looks small next to a full website rebuild.

A man wearing glasses photographs a pair of trainers on a box with his phone, ready for an online shop

Getting started without overhauling your whole site

You do not need to rename every image on your website in one sitting. Start with the pages that matter most for search, usually your homepage, your service or product pages, and any page already getting reasonable traffic. Fix the images there first, then work through the rest as you update other content anyway.

If your website platform makes bulk renaming awkward, prioritise the alt text field over the filename. Alt text is almost always editable without touching the file itself, and it carries at least as much weight for both search engines and screen readers. A recognised UK design and marketing award list named pomegranate a 2025 Top SEO Company, and one of the genuinely unglamorous habits behind results like that is exactly this: fixing small, overlooked details across a site rather than chasing one big change.

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Frequently Asked Questions

What should I actually write in an image’s alt text?

Describe what is genuinely in the picture, in plain, specific language, as though explaining it to someone on the phone. Avoid keyword lists and avoid starting with “image of” or “picture of,” since that phrasing is redundant for the screen readers alt text was built for.

Does renaming old image files break anything on my site?

It can, if other pages or emails link directly to the old filename, so check for that first. Many website platforms let you replace an image without changing its stored URL, which avoids the problem entirely; check your platform’s media library settings before renaming files that are already live.

How long should alt text be?

Long enough to describe the image accurately and no longer. A short sentence is usually enough. Screen reader guidance generally suggests keeping it concise rather than padding it out for search engines, since an overlong description becomes tedious to listen to.

Do decorative images need alt text too?

No. Purely decorative images, ones with no informational content, can have an empty alt attribute. That tells assistive technology to skip past them, which is more useful than a description invented just to fill the field.

Will fixing my image SEO actually move the needle on rankings?

On its own, it is unlikely to transform a struggling page, but it removes a real barrier to being understood by search engines and opens up Google Images as an extra source of visits. Combined with the rest of a page’s SEO, it is a small, cheap fix with no real downside.