Mixed content warning for 3 images

Hi guys,

Please can somebody help me with this – I’m going out of my mind! I have 3 mixed content errors showing on my site which obviously displays the not secure red warning.

These all appear to be images, but when I access my media library, the image urls show as https! So what am I doing wrong and how can I make sure they are not loading as http? The message I get when I check my site on whynopadlock is as follows:

An image with an insecure url of “https://iceatrail.com/wp-content/uploads/2018/04/Valentina-Greggio-4.jpg” was loaded on line: 447 of https://iceatrail.com/.
This URL will need to be updated to use a secure URL for your padlock to return.

I simply can’t find how to change that. I’ve used all the recommended plugins and I’ve descended into a plugin wormhole, whereby I keep getting guidance to install another one and another one. I’d rather fix it manually but I just don’t know how.

How can I fix this?

Thank you!

Paul

The page I need help with: [log in to see the link]