The main culprit.
THE PROBLEM
A photograph from a phone or camera is several megabytes and several thousand pixels wide.
Displayed at 800 pixels wide, the visitor downloads all of it and the browser shrinks it.
WHAT THAT COSTS
Data the visitor pays for Seconds of loading Processing on their device
A TYPICAL BAD CASE
A homepage with six unoptimised photographs is eighteen megabytes.
The same page with properly prepared images is under one.
WHY IT HAPPENS
Uploading straight from a phone or camera without preparation.
Most site owners do not know it is a problem.
WHAT PROPERLY PREPARED MEANS
Resized to the dimensions actually displayed Compressed In an appropriate format
HOW MUCH DIFFERENCE IT MAKES
Frequently the single largest improvement available to a site.
WHERE TO START
Find your largest images. Fix those first.
