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Answer: Alt text is descriptive text that conveys the meaning of an image. Alt text should be short and to the point and communicate the same information as the visual content.

Section508.gov guidelines

• Alt text should not contain unnecessary information or repeat information already provided in the text.
• Write alt text in the same language as the main content.
• Photos: describe the content relevant to the surrounding context; "Dr. Martin Luther King Jr." beats a description of his suit and tie.
• Images that contain text: when possible, do not put text in an image; if one does, include the text word for word in the alt text.
• Logos are never decorative, so they require alt text.
• Decorative images: mark them decorative, or a screen reader may read the file name.

Digital.gov

• All images require alt text for screen readers, and/or a caption.
• Be descriptive, yet succinct, and note if the image is an infographic, diagram, chart, photo, or logo.

See also

• plain-chart-states-its-message
• plain-visual-supports-main-message

Claims

• id: C1 claim: Alt text conveys meaning. source: S1 evidence: "descriptive text that conveys the meaning of an image in digital content"

• id: C2 claim: Alt text should be short. source: S1 evidence: "Alt text should be short and to the point."

• id: C3 claim: Text in images should be included word for word. source: S1 evidence: "include it in the alt text word for word"

• id: C4 claim: Digital.gov asks for descriptive yet succinct alt text. source: S2 evidence: "Be descriptive, yet succinct."

Sources

• [S1] Authoring meaningful alternative text. Section508.gov (GSA). https://www.section508.gov/create/alternative-text/ . License: US government work, public domain. Accessed 2026-11-09.

• [S2] Digital.gov style guide. Digital.gov (GSA). https://digital.gov/style-guide/ . License: US government work, public domain. Accessed 2026-11-09.

License: this note is CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Summary by iinventedlight (AI-assisted). Sources: US federal government works (GSA, GPO, SEC, CDC), public domain in the United States; third-party quotations inside those works were not used. Text was condensed and changed from the originals.

@misc{iil_note_21nshtcb,
  author = {{iinventedlight}},
  title = {{Write alt text that conveys what an image means}},
  howpublished = {iinventedlight Library},
  year = {2026},
  date = {2026-11-09},
  url = {https://iinventedlight.com/library/notes/plain-alt-text-for-images/},
  note = {Permanent ID iil:note:21nshtcb. License: CC-BY-4.0.},
}

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