Image optimisation — make your website faster without losing quality

On most small business websites, images are the heaviest thing on the page — often heavier than all the text and code combined. The good news is that this is the easiest kind of slowness to remove, and you don't need a developer to understand how.

Why images make pages slow

A photo straight from a phone camera can be four or five megabytes. Put it on a web page as-is and every visitor has to download every byte before the image appears — on mobile data, too, and even when they're only there to find your phone number.

An image optimised for the web can do the same job at a tenth of the size. The difference is rarely visible to the eye, but very visible in the loading time.

The three things that actually matter

You don't need to learn everything about image formats. Three steps get you most of the way:

• Correct pixel size. An image displayed 600 pixels wide on screen doesn't need to be 4,000 pixels wide. Scale it down before you upload it.
• Compression. Compression removes data the eye doesn't notice. Around 80 per cent quality looks the same but weighs far less.
• A modern format. Formats like WebP and AVIF give the same quality as JPEG and PNG at a much smaller size. Most browsers now support them.

Do just these three and you've usually solved the problem.

Choose the right format for the right image

There's no single rule that fits everything, but a simple guideline helps:

• Photographs (people, products, premises): WebP or JPEG.
• Logos and icons with sharp edges: SVG where possible, otherwise PNG.
• Graphics with few colours: PNG or SVG.

The main point is to avoid saving a large photograph as a PNG — that makes the file needlessly heavy without improving quality.

Let images further down wait

A trick that costs little and helps a lot is called "lazy loading". In practice it means images further down the page aren't loaded until the visitor scrolls there. The page feels faster because it only fetches what's actually on screen.

Most modern website tools do this automatically. If you use WordPress or a similar system, it's often just a setting to switch on.

Don't forget alt text — for people and Google

Every image should have a short, descriptive alt text. Screen readers use it for people with visual impairments, and it helps Google understand what the image shows. Write what you actually see: "Plumber installing a hot water tank" is better than "image1". Don't stuff it with keywords — describe the image honestly.

How to get started today

You don't have to do everything at once. A simple order:

1. Find your heaviest pages — the homepage and your most-visited landing pages first.
2. Download the images, scale them to the right width, and compress them with a free tool.
3. Re-upload them, and check the loading time before and after.

Even after the most important pages, you'll usually see a measurable improvement.

It connects to the rest

Image optimisation is one of several steps that affect how fast and how high your site appears. It ties closely to why speed affects ranking and to avoiding common technical mistakes. Tackle the images first and you've handled the easiest, most visible part.

Light images aren't a goal in themselves — they're simply one of the shortest paths to a page people are willing to stay on. If you want to know how much your own images are slowing you down, have a chat with us.