A practical checklist for image optimization

Teams tend to reach for this after something has already gone wrong. Run through this the next time image optimization comes up.

Real-world numbers from actual visitors matter more than a score produced on a fast laptop. If it only works because one person remembers to do something, it does not work yet.

The checklist

• Images are usually the largest thing on a page
• Modern formats cut file size substantially at the same quality
• Serving a 3000px image into a 400px slot is pure waste
• Someone is named as the owner
• There is a date to review it again

The reason this keeps coming up

Images are usually the largest thing on a page. In practice this is a scheduling problem more than a technical one. Write the reasoning down alongside the decision, because the reasoning is what changes first.

In practice

Speed is a feature people notice only in its absence, and then they leave rather than complain. Three things worth confirming about image optimization before you move on:

• Someone can say what the current setup is without going to look
• Serving a 3000px image into a 400px slot is pure waste — and you know whether that is true here
• There is a way to tell whether the last change to this helped

Most of the value here comes from doing the first two things, not all of them.