In the future, you may want to try restarting your browser or clearing cache instead of editing the post repeatedly - editing the post doesn't change the proxy URL for the image, so it doesn't force the browser to reload the proxied image.
I do remember seeing your report about the extra content appended at the end of the edited entry, but I was sure it was caused by a browser extension and not our site. Based on these comments, I've narrowed it down to the issue mentioned here:
Re: Pictures working now; old "Save" bug still here
I do remember seeing your report about the extra content appended at the end of the edited entry, but I was sure it was caused by a browser extension and not our site. Based on these comments, I've narrowed it down to the issue mentioned here:
Topic: [Resolved] Edit button shows up in post html « WordPress.org Forums
https://wordpress.org/support/topic/edit-button-shows-up-in-post-html/page/2/