iOS Safari sharing image URL as string instead of image

I'm currently creating an AR web app that allows you to take a screenshot, converts from base64 to a blob file and shows a preview on screen. When shared from chrome it sends the image fine using navigator.share(), but when shared from safari (long tap image and hit share) it instead shares the blob url (blob:https://) as a string. It appears with a 'save to photos' option as well so seems to know it's an image. Is there any way to force it to share the image instead of the url (image.src)?