I believe there is a bug in this plugin.
First off, I have FORCE_SSL_ADMIN enabled in wp-config.php so that all stuff in the admin area is secure.
I also have the 'Internal HTTPS Elements' plugin option enabled.
What happens is that I create a new page for the site. In this new page, I insert a photo. It appears that this plugin is forcing the image url to be https rather than http. Even thought the page will be served from http, the embedded image is https. I'm wondering if the plugin is confused because the image is inserted during a SSL session?
ps. If I disable 'Internal HTTPS Elements' this does not happen, but that is an important option to remain enabled.