How to write alt text, produce accessible diagrams, choose images and copyright standards for GOV.UK.
Alt text and captions
Alt text is used as an alternative to an image for people who use screen readers. Use alt text where you need to help users understand the visual content. Do not always make the alt text a literal description of the image: think about what point the image is making.
One excellent piece of advice is to imagine that you’re reading out the content of the page down a telephone. When you get to the image, what would you say about it to help the listener understand the point the page is making?
If an image is not essential to understanding the content (it’s a logo, for example) or you’ve already covered the same information in text elsewhere on the page, use empty quote marks (“”) as the alt text. There’s no need to duplicate it.
Find out how to publish images.
Use a caption to describe what’s happening in the image, not to summarise the story. Captions are optional. If you do not need one, do not include it.
Sometimes it’s useful to use a diagram to visually convey a concept.
You should consider these things if you’re thinking about publishing a diagram.
This guidance covers diagrams for public and internal use. It does not cover things like network diagrams which need to contain specific terminology and graphics.
Work out whether you need a diagram
Before deciding to use a diagram, you need to work out whether what you’re trying to convey is best done with text, or a diagram supported by text.
If you can convey the information in a clear and succinct way with text then you probably do not need a diagram. If a diagram helps you to make a subject clearer, or summarise a large amount of information, it’s helpful to include one.
Consider whether you can reduce the complexity of the thing you’re trying to convey, and work with a content designer to make sure the text is clear.
Keep diagrams simple
Diagrams need to be clear and easy to understand. Follow the Government design principles, for example by sticking to one idea per diagram.
Work with subject matter experts to strike the right balance between the diagram being too:
- simple and leaving out important information
- complex and unclear
When you’re drawing the diagram, try to:
- follow normal reading direction - users want to read from left to right
- avoid overlapping connector lines
- use simple shapes - and as few different types as possible
- make it clear where the starting point is for process and flow charts
Make sure the diagram is accessible to everyone
It’s important not to rely on colour alone to convey meaning.
Include a brief description of the diagram in the alt text and a more detailed explanation of the diagram in the body text. This is helpful for users who cannot see the diagram.
If you’re using a graph to convey data, consider including a table. That will make it easier for screen reader users to read data in the correct order.
Where possible, publish your diagrams using the SVG image format - this will allow users to zoom in and out.
Test your diagrams
You should test your diagrams with users - including users with access needs.
Image copyright standards
These copyright standards apply to all images on GOV.UK, including those within a publication.
If possible choose images that are free to use. These will usually be either:
- covered by crown copyright - these images are produced by or for government and can be reused by non-government users under the Open Government Licence
- available for reuse under a creative commons licence such as the CC-BY Licence
Paying for third party images
If you pay to use third party images you must:
Buy the right type of licence.
Accredit the image properly.
Buying the right licence
Content on all government websites will be permanently available on the UK Government Web Archive. If you’re using an image which is not covered by crown copyright you must:
- get worldwide rights
- get the rights to use the image forever (in perpetuity)
- get the rights to use the image on anything
- agree the fee
Image licences must not:
- be for a limited time period
- be based on page impressions
Do not use embedded images that remain under the control of the supplier.
Always attribute images to their source, unless it’s an Open Government Licence (OGL) image. OGL images are covered by the statement at the foot of GOV.UK pages:‘Open Government Licence v3.0’.
Credit creative commons images and all third party images. State if the image cannot be reused for free.
Find out where to credit your image and how.
Using images of people
Check with the copyright holder if the people in the image are happy for you to use it.
Get written consent from people if you’re arranging the photography yourself.
Think about the context: avoid showing identifiable people in connection with things that may cause offence.