Note 06 · Resources
Give a small illustration a clear job
An image earns its place when it explains something that the nearby text needs. Its size, description and loading behaviour are part of that job.
Decide what it explains
A diagram can show a relationship that takes several sentences to describe. A purely decorative image can provide atmosphere, but should not carry a necessary instruction. Before adding either, write a short sentence describing its purpose. If the sentence is vague, the page may work better without the extra file.
Keep the text alternative useful
Describe the relevant information rather than the existence of an image. A diagram showing three stages needs a description of those stages or a nearby equivalent explanation. Decorative material can use an empty alternative. The aim is to preserve the reading task when the picture cannot be seen.
Reserve space and keep files local
Set useful dimensions or an aspect ratio so text does not jump when the image arrives. Prefer a small local file when it provides enough detail. Review it at the actual display size; a large source file is unnecessary when a simple shape or modest illustration communicates the same idea.