Write Image Descriptions That Carry the Meaning

Ask what disappears

Ask what a reader loses if an image disappears. A decorative border may need no spoken clutter; a map, diagram, or evidence photograph needs another route to its information. EPUB Accessibility recognizes alternative text and extended descriptions because image jobs differ.

On a field-guide spread, a marsh photograph may need short context. A route map needs destinations, distances, and hazards. A tide chart needs values and units in structured text. One generic sentence cannot do all three jobs.

Describe from evidence

View the image at full size, read caption and nearby text, and retain only what the passage needs. State observable details before inference. “Three figures face a flooded road” differs from “residents flee disaster” unless reliable context establishes that.

Do not repeat an adequate caption. For complex work, put a longer description in text or end matter; for a chart, provide the data. Remove “image of” and use the space for meaning.

Edit it with the prose

Read the description after its paragraph. Name identity, emotion, or motive only when relevant and supported. Keep a description log beside caption and rights record. Replace both picture and description when layout changes.

Specific production checks

For a portrait used only to identify a contributor, a concise name and role may be enough. For an archival photograph used as evidence of a labor strike, describe the visible crowd, signs, location where established, and relevant relationship to the argument. The second needs more because the image does more.

Run a caption-description comparison. If the caption gives date, collection, and credit, use the description for visual meaning; if the surrounding paragraph already explains a graph’s conclusion, provide the values or trend that let a nonvisual reader assess it.