As per the warning in chrome
"Attacker might be able to see the images you're looking at on this site and trick you by modifying them"
According to the console output it's my avatar image that is the unsafe item here, is there anyway you can make HTTPS the default for the whole forum (redirect http to https)?

Yes, it's a work in progress.  Due to Only Me and myself being extremely busy right now we've had to put a lot of projects on hold, but this will be one of them.  Thanks for the suggestion.

Love your work! Any chance the emails could at least use the https links? Is that easier to implement?