How to speed up a slow page: images, caching and scripts
Most slow pages are slow for three reasons, oversized images, no caching and too many scripts, and each can be fixed by hand.
A slow page costs you leads. People leave before it finishes, and the ones who stay are less likely to fill in a form. The good news is that most slow pages share the same three causes, and you can work through them in order of payoff.
Run the page through Google's PageSpeed Insights and write down the loading time of the main content (see Core Web Vitals explained). The report lists the biggest savings first. Work from the top and re-run after each fix, so you know what helped.
Images are usually the heaviest thing on a page. A photo straight from a camera can be several megabytes, when 100 to 200 kilobytes would look the same on screen.
Resize each image to the size it is shown at. A picture displayed 800 pixels wide does not need to be 4000.
Use a modern format such as WebP or AVIF where your site allows it.
Load images below the first screen lazily, so they arrive only when someone scrolls to them. See lazy loading. Do not lazy-load the main image at the top.
Give every image a width and height so the page does not jump as it loads.
A cache keeps a ready-made copy of a page or file so it does not have to be rebuilt for every visitor. Most website platforms have a caching setting or plugin. A content delivery network goes further by serving copies from a location near the visitor. After a change, clear the cache or you may keep seeing the old page.
Chat widgets, trackers, font loaders and sliders each add code the browser must download and run. List every script on the page, ask what each earns you, and remove the ones that earn nothing. For the rest, load them after the page has drawn (the settings are usually called defer or async).
