General image drafting improvements, etc.

It looks like I can't add images to existing drafts if they already contain images. Firefox 102.0.

Steps to reproduce:

Create a post

Upload 1-4 images

Save as a draft

Edit the draft

Upload a new image (deleting one if need be)

Save the draft

Expected:

The draft saves with the new image.

Actual:

The post hangs indefinitely with "Starting..." over the image.

In console, I get an error on hitting save draft:

Uncaught (in promise) TypeError: n.data[t] is undefined