User blog comment:Kirkburn/Technical Update: July 5, 2017/@comment-1757994-20170708191317/@comment-11733175-20170709203220

At a guess, I would suspect the answer to your first question is caused by an upgrade to TLS 1.3 (note that SSL was deprecated just over 2 years ago).

Continuing with the (educated) guesses, the update to serve images over TLS is part of a wider move to move towards HTTPS support across FANDOM - there's a small note about this on w:c:oldschoolrunescape:Forum:Changing the wiki URL Part 2.