SSL website with non-SSL images only content delivery network

Question

I am serving my own CDN using subdomains for static images only, and want to use a SSL cert on the main website.

For example; https://www.example.com would download images from http://cdn1.example.com, http://cdn2.example.com, http://cdn3.example.com and so on.

The CDN subdomains are non-cookie caching only.

Can I still use a registered SSL cert on the main domain www.example.com?

Will browsers report warnings or errors that content from an unsecured source is being download. Is this practice frowned upon.

p.s. Let's assume all my JS and meta tags are from HTTPS sources. Only images are non-SSL.

Answer 1

The browser will not give a full "green padlock" icon and will indicate that while connection is encrypted, there are elements on the page which are not fetched through encrypted connection. This information is only visible if a user clicks a padlock icon.

To answer your question is this a good practice, I would say no, as you should really encrypt all the traffic so your users do not need to worry (if some would), as no one will bother checking which content is unencrypted.