I’d suggest a notice be shown prior to the upgrade so folks don’t get the surprise after commitment. I didn’t see anything about a db upgrade or effecting images when I read the notes prior to upgrading, really glad I used a staging site.
side rant…
IMO, there should be a way to upgrade themes and plugins without down time. WordPress is very poor in this area.
Why can’t two versions of a plugin coexist and WP be smart enough to know which is active? It seems pretty simple logic to me, if v1.0 is active and one uploads v1.1 and activates it, v1.0 becomes disabled. Easy upgrades, easy roll backs. I realize this is not the forum for this suggestion but it is related to the general feeling of the community as it relates to updates. Shiny updates are great but why destroy the previous version when we can be smarter about our approach?