Accessible images
Images can be inaccessible in a number of ways, including:
- Poor image quality
- Contain text that is difficult to read
- Poor colour contrast
- No meaningful alternative text (alt text).
Please do not upload an image that is comprised entirely of text. Text should always be added as text, and images should always be picture-based with a maximum 20% text-to-space ratio if required.
Text alternatives for any non-text content (e.g. photos) should be provided so that it can be changed into other forms people need, such as large print, braille, speech, symbols or simpler language. It is therefore important that:
- information that is conveyed using images is also conveyed with text
- a descriptive text alternative will allow the information to be conveyed to an assistive technology user who may not be able to see the image or non-text element
- avoid flickering, blinking and moving images or text - do not design content in a way that is known to cause seizures. Images that flicker, such as animated gifs, can cause people with photosensitive epilepsy to have seizures. It’s not common, but the results can be serious
- animated images need to avoid flickering between frames
- blinking or moving text and images can be distracting for many users, especially those with certain cognitive disabilities. Web developers and authors are advised to keep moving content to a minimum and give control of moving content to the user via simple play and pause functions
Find out more
- WebAIM has a useful accessibility contrast checker
- Colour Oracle is a free colour blindness simulator for Window, Mac and Linux.
