Image SEO for Small Business Websites: Size, Format and Alt Text

For a local business, photos do a lot of selling. A picture of a finished kitchen, a repaired roof or a cabin porch at sunset tells a visitor more in a second than a paragraph can. Photos are also, on most small business sites we review, the single biggest reason the site is slow.

Image SEO is about getting both sides right: pictures that load fast and that search engines and screen readers can understand. None of it is difficult, and the results are measurable.

The size problem, with real numbers

Modern phones and cameras take enormous photos. That's great for printing and terrible for a web page, where the picture will be shown at a fraction of that size. When a site sends the original file, every visitor downloads megabytes of detail they'll never see.

Here's a real example from this website. The photograph of Watson Lake on our client sign-in page started as a 5,200-pixel-wide JPEG of 2.68 megabytes. The site never sends that file. Instead it sends a resized copy in a modern format, chosen to fit the visitor's screen:

The 1,920-pixel copy that a large desktop screen receives is 163 kilobytes, about 6% of the original. A phone gets the 640- or 960-pixel copy, at 22 or 44 kilobytes. To the eye, on those screens, they look the same as the original. To a visitor on a single bar of LTE outside Chino Valley, the difference is a page that appears in a moment versus one that crawls.

This matters for search, too. The hero photo is often the 'largest contentful paint' that Google measures as part of Core Web Vitals, so a heavy image directly worsens a measurement Google uses. Our Core Web Vitals guide explains the thresholds.

Five fixes for image weight

If your site runs on a page builder, many of these are settings or plugins rather than code. If it's custom-built, they should be part of how the site handles every image automatically, so nobody has to remember.

Alt text: describing pictures in words

Alt text is a short written description attached to an image in the code. Screen readers read it aloud to visitors who can't see the picture, and it's shown if the image fails to load. Google uses it, along with the surrounding text, to understand what the picture shows, which is how images appear in Google Images.

Good alt text describes what's in the picture and why it's there, briefly and specifically:

Not every image needs alt text. Purely decorative images, like background textures or a divider, should have an empty alt attribute so screen readers skip them. If an image contains important words, such as a sign or an offer, make sure those words also appear as real text on the page.

File names and context

Before uploading, rename files from 'IMG_4471.jpg' to something descriptive like 'walnut-kitchen-island-prescott.jpg'. It's a small signal, but it costs nothing. More important is the text around the image: a picture placed next to a paragraph about a kitchen remodel, with a caption saying where and what it is, is easy for Google to understand.

Captions are underrated. People read captions more readily than body text, and a caption like 'Completed in Dewey-Humboldt, spring 2026' is both proof and context.

Video, logos and the other heavy things

Photos aren't the only weight. A background video that plays on load can be many times heavier than every photo on the page combined, and on a phone it's often not even visible in full. If you use video, show a still image first and only load the video when someone chooses to play it, or keep it to a short, heavily compressed clip on larger screens.

Logos and icons should usually be SVG files, a format that stays sharp at any size and is typically tiny. A logo saved as a large PNG is a surprisingly common cause of a slow header. And image sliders deserve a hard look: they load several large pictures to show one at a time, and few visitors ever see past the first slide.

Real photos beat stock photos

There's no direct ranking penalty for stock photos, but they're a missed opportunity. A stock photo of a smiling plumber appears on thousands of other sites. A photo of your own van outside a recognizable local landmark, or your actual finished work, is unique, builds trust, and supports the 'experience' that Google's quality guidelines look for, which we cover in our E-E-A-T article.

If good photos are the bottleneck, a photography session or a simple routine of photographing every finished job pays off quickly. A project gallery gives those photos a home that keeps the site fresh.

A quick image check for your site

The figures above come from how this site handles its own photographs. If you'd like us to check yours, the free audit covers page weight, or get in touch.