Allow images to be marked as decorative.

I'm trying to add images in an interactive book. Some of the images are decorative - not alt text required - however I'm forced to add alt text for them.

If I leave the fields blank then H5P inserts the alt text "new image".

Its good to prompt people to add alt text but there should be a check box to allow for decorative images.

Content types: 

Is there an option to mark images as decorative or remove the alt text from the images?