I would like to add an image to an HTML tag. When I do so, since my images are not in a secure (HTTPS:) environment, users of Explorer get awkward messages about loading secure and unsecure materials. That can be turned off, but I'd rather place a image somewhere that will not cause this problem. Ideas other than creating my own secure location for images?
Are you talking about images hosted by Rollbase or by other servers?
If Rollbase, please provide more info so I could reproduce the issue. Otherwise in custom HTML use full URL starting from HTTPS://
You can also turn off HTTPS on portals (use Edit Portal page).