How to add pinterest functionality to images in blog posts?

I’m new to ghost (excuse my ignorance) and I am hoping to add the ability for users to hover over images embedded in each post and pin/share them on Pinterest.

I’ve followed all of Step 1 in the Pinterest Integration walkthrough ( I’ve copied the script snippet, added it to the Code Injection header (Site header), and saved it but it still doesn’t work. I have tried testing functionality on Mac, PC, and mobile but still no luck.

Here is a current blog post of mine that contains a large image/visual that I’d like to be pinnable:

Update- these have suddenly appeared now without me having taking any action that would have done so (that I’m aware of).