Why Ecommerce Image Optimisation Affects Your Rankings

How to optimise images for SEO

Image optimisation is one of those tasks that is easy to ignore and costly to skip. On an image-heavy store it can be the single biggest drag on speed. Here is why images affect rankings and how to optimise them properly.

Why images matter for SEO

Images affect SEO in several ways at once. Large files slow your pages. Speed is a ranking factor as well as a conversion one. Well-described images can rank in Google image search, bringing extra traffic. Alt text supports accessibility, which matters for users and search engines alike. On a store full of product photos, all of this adds up quickly.

Compress and resize

The biggest win is reducing file size. Resize images to the largest dimensions they actually display at, then compress them so they load fast without visible quality loss. A product photo does not need to be a multi-megabyte file. Smaller, well-compressed images cut load times across the whole store, which helps both rankings and conversions.

Choose the right format

Modern formats like WebP and AVIF deliver the same visual quality at a far smaller file size than older JPEG or PNG images. Switching formats is one of the easiest ways to speed up a store. Most platforms and image tools now convert to these formats automatically, so there is rarely a reason not to use them.

Use descriptive file names

A file named for the product, such as blue-running-shoes.jpg, tells Google what the image shows. A file named IMG_1234.jpg tells it nothing. Name your image files clearly and descriptively before uploading. It is a small habit that helps your images get found in search and reinforces what each product page is about.

Write useful alt text

Alt text is a short description of the image that helps screen readers and helps Google understand the picture. Describe the product accurately and naturally, for example a navy waterproof walking boot. Avoid stuffing it with keywords, which helps no one. Good alt text improves accessibility, supports image search and quietly strengthens the page.

Lazy load and serve responsively

Loading every image at once slows the first view of a page. Lazy loading defers images below the fold until a shopper scrolls to them, so the visible part loads fast. Responsive images served at the right size for each device, ideally through a content delivery network, keep things fast on mobile as well as desktop.

Help Google discover your images

Make sure Google can find and index your images. An image sitemap helps, as does relevant structured data on product pages. Keep your product images unique rather than reusing stock shots every rival also has. Discoverable, original images are the ones that earn a place in image search and bring traffic you would otherwise miss.

Where to go next

Images and speed go hand in hand, so Page Speed and Ecommerce Rankings covers the wider speed picture. Images matter most on product pages, so pair this with Ranking Product Pages on Google. And since most shoppers are on phones, Mobile SEO for Ecommerce shows why fast images matter even more there.

Every guide here sits inside our SEO Guides for Ecommerce Businesses hub, so you can work through the whole store. When you would rather we handled the technical side, our Ecommerce SEO Services page explains how we speed up stores across the UK.