It's hard to believe that one image not https:// on a website will break the SSL and you will see no lock and get an insecure warning!
I have had to turn all my image links on site to /images rather than the website address as most were all pointing from a http://
Really if you host a website with just the http:// and are not overly concerned with using SSL Certificate then your better off. I mainly use SSL because where I work everything has to be secure in order for it to pass through our IT Security blocks! I've had a few members who are in the military who said they can't hardly go anywhere online without the SSL Certificate (GREEN PADLOCK)
Now when you do have the SSL Certificate installed correctly your always having to review your site as if you are a new visitor and test to make sure you can create a new account and it doesn't say this website is insecure! So if you see the insecure warnings I am not doing my job correctly and should most likely fire myself!
By the way I use a standard https:// certificate @ CozWorld.com