Digital accessibility: alternative text
Adding alternative text (or alt text) to images allows people with visual impairments to access information about images via screen readers.
An image must have alternative text if
- The image communicates information or serves a purpose other than decoration.
- The information or purpose of the image is not conveyed in a caption.
If an image is purely decorative, it does not require alternative text. However, it must still be marked as decorative using the alternative text interface. Examples of decorative images may include cover images for your Moodle page or stock images included in a slide deck.
It is not possible to mark images as decorative in Google products. Either plan to include alternative text, or consider not using decorative images.
Alternative text should
- Communicate the meaning of the image, not the appearance.
- Not include phrases like "image of" or "picture of." That information will be conveyed by the screen reader when the alternative text is read.
- Not repeat information in a caption or nearby text.
- Be concise. Some screen readers stop reading alternative text after a certain number of characters. We recommend alternative text be 125 characters or less.
Adding alternative text in Microsoft Word or PowerPoint
The process for adding alternative text is identical in Microsoft Word and PowerPoint for Mac.
To add or edit alternative text in Word or PowerPoint
- Select the image you want to add alternative text to.
- Select the Picture Format toolbar, then select Alt Text.
- Alternatively, right click or control click on the image and select View Alt Text.
- Enter your alternative text in the text box. We do not recommend using the generate alt text for me button at this time.
- If your image is decorative, do not enter alternative text. Instead, toggle on the "Mark as decorative" option.
- Remember that alternative text is not necessary if the image has a caption or text nearby that conveys the same information. If that's the case, mark the image as decorative.
Adding alternative text in Google Docs and Slides
The process for adding alternative text is nearly identical in Google Docs and Google Slides.
To add or edit alternative text in Google Docs and Google Slides
- Select the image you want to add alternative text to.
- Select either Image Options (Google Docs) or Format Options (Google Slides) from the toolbar. You may have to expand the toolbar to see these options.
- Expand the Alt Text area and enter your alternative text in the text box.
- Because it is not possible to mark a text as decorative in Google products, you must add alternative text to each image.
Adding alternative text in Moodle
You will have the option to add alternative text to an image when you add it in Moodle.
To add a new image with alternative text to Moodle
- With editing turned on, in any text area, select the Image option from the text editor toolbar to add your image.
- In the Image properties window, add alternative text in the box labeled "Describe this image for someone who cannot see it."
- If your image is decorative, do not enter any alternative text. Instead, check the box labeled "This image is decorative only."
- Select save image to add your image to the text area. Note that Moodle will not allow you to add a new image using this method unless you have added alternative text or marked the image as decorative.
To add alternative text to an image that is already in Moodle
- With editing turned on, choose the option to edit settings for the area where your image appears.
- Select your image, and then open the Image option in the text editor.
- The Image Properties window will appear. By default, your image will have been marked as decorative. Uncheck that box labeled "This image is decorative only." This box must be manually unchecked, even if you add alternative text to the image.
- Add alternative text in the box labeled "Describe this image for someone who cannot see it."
- Select Save Image to save your alternative text.
