Create accessible materials – Images and diagrams
Using relevant images and diagrams can make content simple, clear and visually engaging. Making sure images are clear and have descriptions, alternative text and good colour contrast can help more people experience their benefits. Only use images that add additional information or provide clarity to the text content.
Relevant pages
Images (Australian Government Style Manual)
People who benefit from accessible images
Images and diagrams can be either digital or printed. They can help people understand and navigate information. It’s not a good idea to remove all images, as that can make information less accessible. Instead provide alternative text (alt text) for your images.
Making images accessible can benefit people:
- Using screen readers, as the alt text can be read aloud or displayed in braille.
- Using speech input software, as they can focus on the image with a single voice command.
- When images are turned off or don’t load, such as mobile users or those with poor internet connection.
Digital images
When you choose and include digital images, you should:
- Make sure all images are clear on different devices such as phones, tablets, computers and more.
- Have meaningful text descriptions and alternative text (alt text). To determine what type of alternative text an image should have, use W3C’s alt decision tree.
- Use images that have more than just text.
Consider if your image:
- Is an appropriate file size (not too big or small).
- Has the subject in focus (not blurry or pixelated).
- Has an appropriate contrast ratio (users are easily able see the subject of the image or read the alt text).
- Isn’t flashing or moving very quickly (if it’s an animated image like a .gif).
Relevant pages
How to make social media accessible: our top three tips (Vision Australia)
Informative images
Informative images are pictures, diagrams or graphs that convey a simple concept or information to users.
Informative images should be made using tools that include alt text. For example, avoid using cascading style sheets (CSS) as alt text cannot be applied to them.
Relevant pages
Informative image tutorial (W3C)
Decorative images
Decorative images do not add extra information to the content. This might be because the image is:
- content that is identified and described in the text
- visual styling
- a picture version of the text
The alt text of decorative images should be either described as null or you should use a tool to mark as decorative.
Relevant pages
Complex images
Complex images contain more content than can be described in a short phrase or sentence. These include charts, graphs and diagrams.
For most complex images, write a short description of the image as alt text on the image, and link to a longer description of the image.
Complex images should never be created using CSS, as alt text cannot be applied to them.
Relevant pages
Captions
Add captions below images. Start with the word ‘caption’ and then add a description of the image.
Vary the words in the alt text and in the caption. Users using the alt text can then have a richer, more equal experience. However, if the caption clearly explains the image, write null in the alt text.
Relevant pages
Printed images
All print images should be clear. This means that access is still possible if the image is enlarged, for example by using software or magnifiers.
Clear images have:
- simple styling, without unnecessary detail
- important details sufficiently visible (such as the thickness of important lines)
- the subject of the image in focus (not blurry or pixelated)
- high contrast (especially between foreground, subject and background)
- labels that are short, clear and close to the item they are labelling.
Print colour and contrast
Colours will look different depending on the printer. If you are printing the images, you should:
- Make sure printed images are clear and have good contrast ratio.
- Print test pages to test the clarity of the images.
- Consider using standard colours to make sure they are consistent. For example, the Pantone matching system.
- Edit images or simplify them to increase their clarity when printed, if needed.
Image alternatives for print
Consider providing images in alternative formats, especially if materials are long or have many images. You should:
- Provide participants with digital copies that contain images with alt text.
- Use captions alongside images.
- Use enlarged, clear images in large-print copies.
- If images will be described to participants more than once during the activity(s), you may want to provide the image description alongside the image. This will mean image descriptions are consistent for all participants.
Relevant pages
Images (Australian Government Style Manual)