Accessible media helps more participants take part. The most important piece is Alt text — a short description you add to each image so people using a screen reader, or anyone whose image doesn't load, still get the point.
Add alt text to an image
When you add an Image element to a slide, its settings include an Alt text field. Write a short, meaningful description of what the image shows and why it matters — up to 500 characters. If an image is purely decorative and carries no information, you can leave it out.
Captions and clear file names
You can also add an Image caption, shown under the picture, which everyone sees — useful for a source, a note, or extra context. For anything participants download, use a clear file name so the name itself tells them what the file is.
Don't rely on one channel alone
Avoid relying only on colour, sound, or small text in screenshots. If a screenshot makes its point with a red box, say the same thing in words. If audio carries key information, add written context around it too, so the activity still makes sense without sound. See Adding images to a learning journey and Adding audio to a learning journey.