A quick housekeeping note for myself: I used this article to fix the Add Media function within WordPress, which was disabled with the installation of Jetpack. Jetpack is handy for lots of small things, so I had to get the two to play nice. One parameter string changed and we’re back in business.
Update: This fix broke the Update function in the main editing window; after a minute or so the Update, Preview, and Publish functions timed out and became unavailable. So I set it back.