Instead of changing all the links to https://, change them to just //
<img src=”//www.domain.com/image.gif” alt=”” />
Also if the images or scripts are located on the same domain, you can access them relatively, rather than absolutely:
<img src=”image.gif” alt=”” />
When using this method your browser will know that it must load the image securely, if the web page is being loaded securely, but it will also load the image normally if the page is not being accessed securely. The image/video will still need to be available on the other servers securely(as https). This is probably the best way of getting rid of the pain in the butt “Do you want to display the nonsecure items?” warnings, or browser bar not being green!
If you are on WordPress you can use plugins like SSL Insecure Content Fixer which is a free plugin.
If you have not picked up my training on how to get SSL for Free for your domain, get it here https://crowley.link/secure-your-website
I hope this helps you out!
EDIT: You can Right click on your page and view source. Then do a “Control+F” to do a search type in http:// then you will see everything that is not secure, change those links as instructed above.