When a site is slow the server gets blamed first, but that is rarely where the problem lives. What keeps a visitor waiting is usually uncompressed images, too many plugins and third party scripts loaded from elsewhere.
Images are almost always first
A photo straight from a camera is four to eight megabytes. Saved at the right dimensions in a modern format, the same image drops to two hundred kilobytes. That is a twentyfold difference, and on a mobile connection it translates into seconds.
Images should be served at the size they are displayed. If a picture shown at three hundred pixels wide is a four thousand pixel file, the browser downloads the excess and throws it away, and the visitor still waits for it.
Third party scripts pile up quietly
A chat bubble, an analytics tool, an advertising pixel, an embedded map, a font service. Each looks small on its own, but every one connects to another server, and if that server is slow so is your site. It is a delay outside your control.
- Remove every script you do not actually use, since most sites carry tools added on launch day and never revisited
- Serve fonts from your own domain, an externally loaded font both slows the page and hands visitor data to a third party
- Instead of embedding a video, show a cover image and load the player only when it is clicked
Speed is a ranking factor
Google measures page experience through loading time, layout shifting and how long it takes before the page responds. These alone do not carry a page to the top, but between two pages of equal strength the faster one wins.
The commercial side is clearer. On pages that take more than three seconds a noticeable share of visitors leave before anything appears. The person lost is subtracted from sales, not from rankings.
