The "may slow the page" prompt is only a client-side nudge — the server
hard-limits uploads at 8 MB. 1 MB was arbitrarily low and nagged on
perfectly normal hero images. Bump to 5 MB (still well under the hard cap)
and pull the threshold + message into a single tooLargeToUpload() helper so
the background, moon, and image upload paths stay in sync.
Claude
7e8ffeee6f