Case study
JDL Automation
jdlautomation.co.uk
Every image in the library re-encoded to AVIF, with WebP behind it and the untouched original behind that. No redesign, no rebuild, and nothing deleted.
less for a visitor to download, measured across 16 pages of the live site.
The heaviest page
Averages hide the page that actually
hurts. On jdlautomation.co.uk it is /, which went from
2.5 MB to 1.4 MB —
44.0% lighter. That is the page a visitor on a phone was waiting for.
Page by page
Every page, weighed as a browser loads it
HTML, stylesheets, scripts and images together — not a lab score and not a
projection. Re-runnable at any time, because the page carries both halves of its own
comparison: the AVIF a modern browser takes, and the original still sitting in the
<img> fallback inside it.
| Page | Before | Now | Lighter |
|---|---|---|---|
| Home page | 2.5 MB | 1.4 MB | 44% |
| Automatic doors | 2.3 MB | 1.4 MB | 42% |
| Recent projects | 2.3 MB | 1.4 MB | 40% |
| Automatic gates | 2.2 MB | 1.3 MB | 40% |
| Automatic barriers | 1.5 MB | 980 KB | 36% |
| Industrial doors | 1.5 MB | 916 KB | 39% |
| Peterborough single door automation | 1.3 MB | 1014 KB | 25% |
| Speed lanes | 1.3 MB | 838 KB | 37% |
| Horning gate automation | 1.1 MB | 893 KB | 18% |
| Norwich cantilever gate installation | 1012 KB | 844 KB | 17% |
| Newmarket road automatic door | 1002 KB | 829 KB | 17% |
| Blog | 881 KB | 765 KB | 13% |
| Our services | 846 KB | 648 KB | 23% |
| Stansted double swing door automation | 831 KB | 750 KB | 10% |
| Bury st edmunds double swing door automation | 807 KB | 734 KB | 9% |
| Contact | 565 KB | 565 KB | 0% |
| Every page | 21.8 MB | 15.0 MB | 31.1% |
The images alone came down 58.8%. The whole-page figure is lower because every page also carries text, layout and code, which this work does not touch — and the whole page is what a visitor waits for, so that is the number quoted at the top. Four of these pages offer several image sizes and the browser picks one by screen width, so those rows read the first candidate rather than a guaranteed download.
What was not done
Nothing was rebuilt, and nothing was thrown away
Originals are untouched
The AVIF and WebP files sit alongside the originals, never over them. Deactivate the plugin and the site serves exactly the bytes it did before, because those bytes never moved.
No browser is left behind
Serving uses <picture>.
Anything that cannot read AVIF takes the WebP, and anything that cannot read either takes
the original. Nobody sees a broken image.
The design did not change
Same theme, same layout, same photographs at the same dimensions. Put this against a screenshot from the week before and it should be indistinguishable.
Want the same measurement on your site?
The analyser fetches your real images and re-encodes them, so the figure you get is yours, not an average.
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