How to make images upload as HTTPS:

I am having SSL issues, which I’m sure everyone has at some point. I’m trying to secure some insecure URL’s. I’ve managed to get to some of them in the main page to change their URL’s to link https but some of the images – I’m unsure where to access them in the CSS and I’m unable to simply change the URL of the image.

Can someone help explain where to find the rest of the image links? Or how to re-upload the images to load as https instead of http? Simply re-uploading them doesn’t work.
I’m trying to avoid using relative links as well.

Thank you.

The site I need help with is askpace.com.