I'm building a drag-and-drop image upload. My requirement is that all images are loaded from their base64 representation, not from a URL (for privacy reasons).

When the user drags an image from the file system, conversion to base64 is easy. But I haven't found a way to do it for images dragged and dropped from another browser tab.

I see that ondrop I can get the image's URL using e.dataTransfer.getData('text/uri-list') but that would violate my requirement.

According to this answer from 2014 what I'm trying to do simply isn't possible. But it's old so I'm hoping things have changed.

I have inspected the e.dataTransfer object and played with its various properties but haven't found anything promising.