複雑な画像：グラフ、地図、長い説明

Some images carry too much information for a short phrase. Charts, maps, and diagrams need a longer description plan.

Even a complex image still gets a brief alt that names it, like a bar chart of monthly sales for 2024.

The short alt names the image; a nearby long description then conveys the actual data or relationships it shows.

A great long description gives the takeaway, like sales peaked in December, not a dry list of every single value.

For charts, the strongest alternative is often a real HTML table with the same numbers right below the graphic.

You can place a long description on the page and connect it with aria-describedby pointing to its element id.

Wrap an image and its visible explanation in figure and figcaption so the pairing is clear to everyone.

A map image is useless without the underlying facts, so provide an address, directions, or list as the text equivalent.

For a flowchart, describe the steps and their order in prose, so the logic survives without the visual layout.

Make sure the long description is easy to find. A hidden text equivalent users cannot reach is no help at all.

The richer the image, the more your text equivalent must do. Let the image's complexity set how much you write.

Choose the best plan for a complex chart.

You did it! Complex images get a short alt plus a real text equivalent, a data table, figcaption, or aria-describedby that conveys the insight.