- all content in an image (such as axes, keys and other labels) and footnotes must be easy to read for someone with typical eyesight
- upload a larger version of the image so users can click on it to enlarge it if chart labels are not easily read
- write out acronyms in full or clearly explain them
- do not use red and green together, as it is difficult to distinguish between them
- make sure there is clear distinction between different lines
All images must have alt text, or alternative text. When you hover over the image, a box will appear with a brief, accurate description of the image. Screen readers read this out for people with visual disabilities.
Alt text should be around 15 words and summarise the main trend of the chart; it can duplicate the descriptive chart title. It should not repeat content in the main text.
Images must be no more than 600 pixels wide but can be longer than 600 pixels. However, consider usability when determining the length of an image; it needs to be fully visible on-screen without too much scrolling.