Web Content Accessibility Guidelines a guide to the accessibility requirements
1 Perceivable

1.4.9 Images of Text (No Exception)

Conformance level: AAA
Criterion released in WCAG version: 2.0

Official description of the success criterion

Images of text are only used for pure decoration or where a particular presentation of text is essential to the information being conveyed.

What to do?

Avoid images of text in all circumstances.

Why is it important?

Ensures text is accessible, resizable, and customizable.

More about this criterion elsewhere