A small business had a website that everyone agreed felt slow, and a quote in hand to rebuild it. The homepage took roughly eight seconds to appear on a phone.
The build was fine. The homepage was carrying eleven photographs straight off a phone camera, several of them over four megabytes each, being shrunk by the browser to fit a space a fraction as wide.
Why it happened
Nobody did anything wrong. Someone took good photographs and uploaded them, which is exactly what the content editor invites you to do. Nothing warns you that the file is enormous, and on the office wifi it looks instant.
The visitor on mobile data downloads every byte of the original before seeing anything. That is the entire gap between how a site feels to its owner and how it feels to a customer.
The fix, and the better fix
Resizing and compressing the existing images took about forty minutes and brought the page from eight seconds to under two. No rebuild, no redesign, no new hosting.
The better fix was making it automatic: images now get resized and converted on upload, so the next person who adds a photograph cannot recreate the problem. A fix that depends on everyone remembering is not a fix, it is a warning.
Worth doing today
Open your site on a phone, on mobile data, away from your own wifi. That is the honest test and it takes a minute.
If it drags, run the homepage through a free speed test and read the list under the score rather than the score itself. If the top items mention image sizes, you have found it, and it is the cheapest problem on that list to solve.
Before accepting a quote to rebuild, it is worth being certain the problem is the site at all. A redesign and a findability problem look identical from the inside and cost very different amounts.
If your site feels slow and you would rather not guess, describe what you are seeing and you will get a straight read on whether it needs work or just tidying.