How to Write Alt Text for AEO
Write alt text that describes the image's actual content and meaning — not a filename like image1.jpg, and not stuffed keywords. Pair it with a descriptive filename and caption, and restate any chart's numbers in the text, because a figure trapped in an image may not be read by multimodal AI.
Write alt text that describes the image's actual content and meaning specifically — not
image1.jpg, and not stuffed keywords. Pair it with a descriptive filename and a
supportive caption, and restate any chart's numbers in the text, because a figure trapped
in an image may not be extracted by multimodal AI.
Quick answer
Describe what the image shows and means, plainly and specifically. Give the file a descriptive name, add a caption where it aids understanding, and for charts, restate the numbers in the surrounding text — because an engine may never extract data locked inside an image.
What should alt text actually say?
What the image shows, in specific, meaningful terms. "Diagram of a compression fitting
joining two copper pipes" beats both image1.jpg and a keyword-stuffed string. Alt text
serves accessibility first, and that same clarity is what a multimodal
engine uses to understand the picture. Describe the content and its point.
Why do filenames and captions matter?
They're extra signals an engine reads for free. A descriptive filename reinforces the subject; a caption adds context a reader needs to interpret the figure. Neither replaces alt text — together they build a clearer picture of what the image contributes.
What about data trapped in charts?
Get it out of the image. A chart's numbers may never be extracted from the pixels, so state the key figures in the surrounding prose. That way the data is readable and citable regardless of whether the figure itself is parsed.
- 1
Descriptive filename
Rename before upload — annual-ai-citation-rate-2026.png, not chart.png. It's a free, permanent signal about the content.
- 2
Specific alt text
Describe what the image shows and why it matters, in plain language. No generic filenames, no keyword stuffing.
- 3
Supportive caption
Add a caption where it helps a reader interpret the figure — the source, the takeaway, the units.
- 4
Restate key data in text
Write the chart's main numbers into the body copy so an engine can read and cite them even if the image isn't extracted.
Where to go next
Go deeper on AEO for images, see which content formats AI cites most, and review what multimodal means for how engines read your media.
Frequently asked questions
- What makes good alt text for AEO?
- Good alt text describes what the image actually shows and means, specifically and in plain language. Avoid generic filenames as alt text and avoid keyword stuffing. The goal is to let a multimodal engine understand and potentially cite the image's content.
- Do image filenames matter for AI?
- Yes. A descriptive filename like copper-pipe-fitting-diagram.jpg gives an engine and a human another clear signal about the image, while image1.jpg gives nothing. Name files for their content before uploading.
- Why restate a chart's numbers in the text?
- Because a figure trapped inside an image may not be reliably extracted. Stating the key numbers in the surrounding text guarantees the data is readable and citable even if the chart itself is never parsed.