Don't make attachment elements for images with https:, http: or data: urls. Clients such as Mail would expect pasting or dropping an image with src="https://..." to result in the source URL being preserved (i.e. staying as remote images) instead of creating image attachments out of them.
<rdar://problem/36200381>
Created attachment 330159 [details] Patch
Created attachment 330160 [details] Updated bug title
Comment on attachment 330160 [details] Updated bug title Thanks for the review!
Comment on attachment 330160 [details] Updated bug title Clearing flags on attachment: 330160 Committed r226340: <https://trac.webkit.org/changeset/226340>
All reviewed patches have been landed. Closing bug.