New one page site: "Some parts are insecure...."

[morbea]

I just installed and “Enforced” letsencrypt on a new single page https://taxiaguachica.com hosted by siteground. Upon visiting I see:
Firefox says "Parts of this page are not secure such as images"
Google Chrome says "Your connection to this site is not fully secure"
It is created with WP/divi, has one photo, some html that converts two phone numbers (text) to links to visitor’s cellular dialer, and a plugin that displays a phone icon and also creates a dialer
There is no function on the site which requests or receives information
Command Line???
Hosted by Siteground
My operating system test visited with windows 8.1 and Sierra 10.12.6
My web server is (include version): Host? Linux is this what you’re asking?
My hosting provider: siteground
I’m using Cpanel/ wordpress

Is there something I need to do with photos? or is it a plugin?
Thanks

[rg305]

Verifying the site with: https://www.whynopadlock.com/
Shows an image source:
http://taxiaguachica.com/wp-content/uploads/2017/10/AquachicaPanorama-1600-608.jpg
Which should be HTTPS (not HTTP)

[morbea]

@rg305

Verify the site with: https://www.whynopadlock.com/

Wow, thanks! Narrows it right down to the single photo. It's listed on the web as https, but http within siteground, I'll just need to figure how to fix that - sure there is a simple toggle for that.

Thanks again. I almost feel cheated - so used to struggling for hours, ha!