- All images unless they are purely decorative images.
- Alt text is not supported for tables at this time.
Content
- Do not repeat or rephrase the caption.
- Keep the description brief—no more than 150 characters, including spaces and punctuation.
- Focus on information important to the reader and leave out irrelevant details.
- Use keywords and include only essential information. It is not necessary to include “photograph of,” “image of,” or similar wording.
- Include any text depicted in the figure if space permits.
Format
- Remove HTML/SML control characters (<, >, &, “, ‘).
- Delete or replace dashes with words (e.g., “23–28” should be written as “23 through 28” or “23 thru 28” to save space).
- Spell out uncommon symbols. Common symbols—for example, º, %—are acceptable.
- Limit use of punctuation, which may not be interpreted as intended (e.g., slashes, colons, ellipses, and parentheses).
- Avoid acronyms when possible although sometimes an acronym can be used effectively by adding hyphens between the letters.
- Spell out units of measurement (e.g., “km” should be “kilometers”; prime and double prime characters should be spelled out as “feet” and “inches,” respectively) but some abbreviations will work (e.g., “thru”).
- Numbers may need to be spelled out.
- Check that your character count does not exceed 150 characters. Note that some figures will require a longer description but, if possible, include that information in the text or caption.
- Listen to the alt text using read-aloud technology to check for issues.
Alt text with no context:
Denver skyline with Longs Peak in the background
Alt text in a book about winter sports:
Denver skyline with Longs Peak prominently visible in the background, showing Denver’s proximity to the Rocky Mountains
Alt text in a book about air quality:
Denver skyline with Longs Peak in background, seen through a haze of pollution
Alt text with no context:
Five pot sherds with scale measured in centimeters
Alt text in a book about archaeology in Louisiana:
Five examples of Early Woodland period Tchefuncte pottery sherds from Midden A
Alt text in a book about the Tchefuncte potters:
Five examples of Tchefuncte pottery sherds that show decorative patterns and laminations and measuring between 2 and 9 centimeters
Alt text with no context:
Solo hiker walking on a mountain trail in Bavaria
Alt text in a book about geography:
The area around the Hochgrat in Bavaria, which depicts panoramic views at the top of a mountain trail as part of the Allgau Alps
Alt text in a book about mental health:
[no alt text needed because figure is purely decorative]
Alt text:
Bar graph of the average monthly snowfall at Alta Guard for the months November through April
Note:
Specific information from the graph must be described in the caption or the text.
