How to Write Accessible Alt Text for Academic Images

An academic image alternative should convey the information needed in its teaching context. Start by asking what a student is expected to learn or do from the figure, then inspect the actual source and surrounding explanation.

Charts and diagrams

For a chart, identify variables, units and the relevant comparison. Do not invent values or trends that are absent from the source. A process diagram may need its stages and relationships, including arrow direction. A photograph may require details of a laboratory setup rather than a generic description of objects.

These are instructions for evaluating real figures, not reported customer examples or measured model outcomes.

Complex material

A short description can identify the image and point to a fuller accessible explanation. A long description or appropriate data representation should preserve the information the task requires. The right form depends on the actual content; one fixed word count or mandatory table does not fit every figure.

Mathematics may need an evaluated structured representation or equivalent explanation. A sentence reading symbols is not automatically an adequate substitute for navigating the expression. Check meaning and the intended reader/assistive-technology environment.

Purpose and review

Informative and decorative images need different treatment in the delivery format. An image used as a control also needs an accessible name conveying its function. Do not mark instructional content decorative to remove a warning.

W3C's image tutorials explain the purpose-based approach. Review generated descriptions with subject and accessibility context; presence of text is not proof of accuracy.

Aelira Core is beta software. Supported workflows can apply eligible partial fixes and record outcomes, but some inputs need manual work or cannot produce a downloadable remediated file. Review the actual saved output, unresolved findings and content preservation before publication. Automated scores describe implemented checks rather than accessibility conformance. Inspect the public source and release documentation and evaluate a representative authorized sample before planning a rollout.