Image SEO for small business websites: alt text, file names, size and formats

Good image SEO comes down to four habits: give meaningful images appropriate text alternatives, give the file a descriptive name, keep it small enough to load quickly, and put it next to the text it relates to. Google identifies alt text as the most important attribute for providing image metadata. These habits also make your site easier to use for people with screen readers and slow connections. (Google Search Central)

Below is what each habit involves, what Google says, and a short checklist you can use whenever you upload images.

Why images matter for a small business site

For many service businesses, photos do a lot of selling: finished projects, the shop front, the team, the product in use. Images can also appear in Google Images and in image results within normal search, which gives people another way to find you.

Images also have costs. They are often the largest part of a page's size, so unoptimised photos are a common reason pages feel slow on mobile. (Google Search Central, Image SEO best practices, last updated 2 Mar 2026, checked 26 Oct 2026)

Use real image tags, not background images, for important pictures

Use standard HTML image elements to help Google discover your images. It looks for <img> elements with a src attribute, and it says it doesn't index CSS background images. An image sitemap can also help Google discover image URLs. (Google Search Central, checked 26 Oct 2026)

In practice:

• Photos you want found (your work, your products) should be added as normal images in your website builder, not set as a section background.
• Decorative backgrounds — textures, banners, patterns — can stay as CSS backgrounds. They don't need to be indexed.

If you're not sure which you're using, right-click the image in Chrome and choose Inspect. An <img> tag means it's a normal image.

How to write alt text

Alt text (the alt attribute) is a short text description of an image. Screen readers read it aloud, browsers show it if the image fails to load, and Google uses it, along with the surrounding page, to understand the image.

Google's own example shows the progression from bad to best:

(Google Search Central, checked 26 Oct 2026)

For a business site, that translates to:

• Describe what's actually in the picture, specifically. "Renovated HDB kitchen with white quartz counter and grey cabinets" is more useful than "kitchen" or "renovation Singapore best kitchen contractor".
• Include context only where it's true and useful. If the photo is of a real project in Tampines, saying so is fine. Adding locations or services that aren't in the photo is keyword stuffing.
• Keep it short. A sentence or less is usually enough.
• Usually skip "image of" or "photo of". Screen readers already announce that it's an image. Mention the medium when the distinction between a photograph, painting or illustration matters. (W3C, Tips and Tricks)
• Don't repeat nearby text unnecessarily. If an image adds no information beyond text right next to it, an empty alt attribute can avoid repetition. If it adds meaning, describe that meaning briefly. (W3C alt decision tree)

When an image should have empty alt text

Not every image needs a description. Purely decorative images — dividers, background flourishes, a stock photo that adds atmosphere but no information — should have an empty alt attribute: alt="". That tells screen readers to skip it.

Leaving the attribute out entirely is worse, because some screen readers will read out the file name instead. (W3C Web Accessibility Initiative, Decorative images, checked 26 Oct 2026; for a quick way to decide, see the W3C alt decision tree)

Images that are links or buttons

If an image is the only content of a link or button — a logo linking to your homepage, or an icon used as a button — its alt text should describe where it goes or what it does, such as "[Business name] home" or "Call us", not what the image looks like. If equivalent visible text within the same link or button already names the destination or action, and the image adds no other information, use alt="" on the image to avoid repetition. (W3C, Functional images)

Name your files before you upload them

Google recommends descriptive file names over generic ones, and gives the example of my-new-black-kitten.jpg being better than IMG00023.JPG. (Google Search Central, checked 26 Oct 2026)

This is a small factor, but it costs nothing if you do it before uploading:

• Use a few descriptive words, separated by hyphens: bukit-timah-condo-bathroom-renovation.jpg.
• Avoid camera defaults (IMG_4821.jpg, DSC0012.jpg) and screenshots named by date.
• Don't stuff file names with keywords.

Our practical recommendation is to focus on new uploads rather than renaming existing images just for SEO. Renaming can change the image URL and break references. If you do change a URL, update its references and ask your developer to preserve access from the old address with an appropriate redirect.

Choose a sensible format and size

Google can index BMP, GIF, JPEG, PNG, WebP, SVG and AVIF images, and the file extension should match the actual file type. (Google Search Central, checked 26 Oct 2026)

For most small business sites:

Our guide to logo file formats covers logos in more detail.

On size:

• Resize for the job. A 6,000-pixel-wide photo straight from a phone is usually unnecessarily large for ordinary website content. Around 1,600–2,000 pixels wide for content images, or around 2,500 pixels for a banner, can be useful starting points. These are rules of thumb, not Google requirements or universal limits: check the displayed dimensions, screen pixel density and image quality, and serve responsive sizes.
• Let your platform create smaller versions. Most modern website builders and WordPress generate several sizes automatically and serve the right one using responsive image markup (srcset). Google supports this and recommends always keeping a fallback src. (Google Search Central)
• Check the result. Run your key pages through PageSpeed Insights. Look for Improve image delivery, which highlights opportunities to reduce image download sizes through compression, formats and responsive sizing. Lighthouse 13 replaced older audits such as "Properly size images" and "Serve images in next-gen formats" with this insight. (Chrome, Improve image delivery; Lighthouse 13 changes)

Lazy loading: use it below the fold, not at the top

Lazy loading defers downloading off-screen images until they are needed, often as they approach the visible area. It can save data and reduce competition for resources needed for the first view. Check whether your platform enables it; browsers support it through loading="lazy".

Two cautions:

• Don't lazy-load the main image at the top of the page. Google says not to lazy-load content that's visible straight away, and web.dev research found that lazy-loading above-the-fold images slowed down Largest Contentful Paint, one of the Core Web Vitals. (Google Search Central, Fix lazy-loaded content, last updated 10 Dec 2025; web.dev, The performance effects of too much lazy loading, both checked 26 Oct 2026)
• Images must load without clicks or scrolling tricks. Google doesn't scroll or click on pages, so images that only appear after an interaction (such as a "load more" button with no separate URL) may not be found. The browser's built-in lazy loading is fine. (Google Search Central)

If your hero image loads slowly, check whether your theme or a plugin is lazy-loading it. Switch lazy loading off for images visible when the page first opens, especially the image that forms the Largest Contentful Paint (LCP). Being the first image in the article alone doesn't determine whether it is initially visible.

Put images next to the text they relate to

Google uses the page around an image — headings, captions and nearby text — to understand what it shows, and recommends placing images near relevant text. (Google Search Central, checked 26 Oct 2026)

That means:

• A photo of a completed office fit-out belongs on the office fit-out page, near the description of that work, not in a general gallery with no text.
• Short captions help people as well as search engines: "Reception area, completed March 2026" says more than no caption at all.
• If a page has a main image, Google lets you indicate your preference with structured data or the og:image tag. Choose a relevant, high-resolution image, and avoid logos, images with lots of text and very wide or tall crops. Google still chooses its preview automatically. (Google Search Central) The same og:image helps specify a preferred social-sharing preview rather than guaranteeing what an app displays — see our guide to fixing link previews.

Images and AI search

Google advises keeping important information in text form so it can be used in its AI features. (Google Search Central, AI features and your website, checked 26 Oct 2026)

So if a key fact lives only inside an image — prices on a poster, opening hours in a graphic, a menu as a photo — repeat it in normal text on the page. Search engines and AI tools can read it more reliably, and so can visitors on small screens.

A quick checklist for every upload

1. Does the image add information or provide a link/button's accessible name? Supply the appropriate description or action; if purely decorative or fully redundant to equivalent nearby text, use alt="".
2. Is the file named descriptively, with hyphens?
3. Is it resized to a sensible width and saved as WebP, AVIF or JPEG (photos) or SVG/PNG (graphics)?
4. Is it added as an image, not a background, if you want it found?
5. Is it near the text it relates to, with a caption if useful?
6. If it's visible when the page first opens, especially if it is the LCP image, is lazy loading switched off for it?
7. Is any important information in the image also written in text?

What's in your control, and what isn't

In your control: alt text, file names, formats and sizes, where images sit on the page, and whether key information is also in text.

Not in your control: whether Google shows your images in Google Images or search results, how it ranks them against other sites, and which thumbnail it chooses. Good image practice makes your images easier to understand and faster to load; it doesn't guarantee visibility.