When you are designing courses or content, well-chosen images can break up a text-heavy page, enhance meaning, or set a mood. Sometimes they are worth a thousand words!

To be accessible, most images and other visuals require Alternative Text (alt text), a non-visual way to convey meaning.

Alt text provides several benefits:

• Because screen reader users cannot see images, alt text conveys the image's meaning to users.
• In cases where an image is not loaded into a web page, the alt text is displayed instead.
• Search engines use alternative text to assist in search results.

Most software programs offer a simple means to add alt text. While editing, look for a picture options panel or right-click the image.

The Art of Writing Alt Text

Good alt text depends on context and meaning. Although technology is getting better at recognizing what an image depicts, algorithms alone cannot understand what an image means within the context of the overall page. Subject matter experts are always the best judges of the information an image is intended to convey. For example, a picture might represent an ordinary dog, or it might represent Charlie, Newton, or Ivy–Miami’s most famous golden retrievers.

Consider why you have chosen a particular image and what you hope it will convey to your audience. Start by asking yourself these questions:

• What is the content and function of this image?
• If this image were deleted, would the reader lose important information?

When an image does not meaningfully contribute to the page's content or functionality, then it can be marked as “decorative” or as an “artifact”—no alt text required. Screen readers will skip decorative images, just as if they “didn’t happen.

Furthermore, a detailed description in the text alternative is not usually needed for a captioned image or one that is thoroughly explained in surrounding text. For example, an image of a chart or graph can be described briefly in the alt text (e.g., "Bar chart showing a 10% increase in revenue") and raw data can be provided in a table or long description in the visible caption below the image.

But as a rule, the following images need alt text:

• Meaningful photographs, diagrams, charts, graphs, or infographics.
• Company or organization logos (on their first occurrence).
• Icons that convey status (like a "Warning" icon) or serve as buttons.
• Images of static text or mathematical equations.
• Any image that serves as a link or a clickable map.

Best Practices for Alt Text

Writing effective alt text ensures that the meaning and intent of your visual choices are accessible to every reader, regardless of how they interact with your content. Here are some quick tips for getting started with meaningful alt text:

• Aim for one or two descriptive short sentences to describe the image, under 200 characters in total. The file name is generally not appropriate as a text alternative.
• Avoid including "image of" or "picture of" within the alternate text. A screen reader will automatically state "graphic" before reading the alt text. However, you can include relevant descriptors like ‘chart’ or ‘painting’.
• Similarly, for images that double as links, the screen reader will identify the element as a link. Focus alt text on where the link is taking the user (e.g., "View Miami University, Admissions Page").
• Avoid images of text. If you must use an image that contains text (like an infographic or a quote), every word in that image must be included in the alt text. If the text is lengthy, provide a transcript in the body of the page.
• Use proper grammar, spelling, and punctuation. Screen readers can change vocal inflection to emphasize a question mark or period. Do not include any hard line breaks in your image description.
• When using generative AI to compose alt text, default to the Reasoning (pro) model for the AI tool you're using. For best results, write a specific prompt and request more than one output to choose from. Always manually verify the output.
• For assistance with alt text, visit the AccessMU Center website, attend a drop-in session (at right), or contact AccessMU to set up training for you or your department.