Alternative text or alt text provides a textual alternative to non-text content in web pages. It is especially important for students who may have a visual impairment that prevents them from seeing your images or if a student’s chosen browser cannot display the image. Alt text should be added to every image in your slides and exercises to ensure that your content is accessible to all students.
See this article from WebAIM, which goes into detail on the importance of alternative text and its place in web accessibility.
Adding alternative text
Course images are added using the following format.
The alternative text is placed between square brackets, located to the left of the parentheses containing the image URL and resizing, and to the right of the exclamation point.
Alt text should provide sufficient description for learners to understand what the image or plot shows without seeing it. Here is an example of alt text from the course Introduction to Regression with statsmodels in Python:
A scatter plot of the total payment versus the number of claims. The payment increases as the number of claims increases.
This alternative text provides sufficient detail for someone to gain the key insights from the following plot without viewing it.