Now, only media images have alt tags. Please add alt tags for all images
Hi there @Jim_H 
Happy to inform you that now you can add Alt text for the images:
However, if you are using an image as a background option in the Image Slide type, no alt text is needed there. The image is set not through the <img>, but through the styles for the <div>. As a result, it’s not possible to add alt text, and screen readers won’t recognize or request it.
This is only a part of our major update. Find more info in this post 