The best solution would be to buy a globally trusted https certificate and install it to your webserver.

Ok, good idea!
But that will not fix my old posts, and like things are now it seems I can not post any new images, or link to any old ones, which is sort of discouraging.

Then you should ask Emmanuel to be kind enough to update the links to images in all your old posts to https, or publish the images again in a new post.

Xiste suggested something like that and was told to be cool with me

CEC