Pop-Up using Image Needs to Link to Outside External Source

[Musette]

This is the code I found, that creates a pop-up when my customers click a link for Prop 65 on certain product pages. (Shout out to Alex for the code base):

<a href="https://cdn.shopify.com/s/files/1/1322/7183/files/pop_up2.jpg?v=1637351122" target="popup" onclick="window.open('https://cdn.shopify.com/s/files/1/1322/7183/files/pop_up2.jpg?v=1637351122','popup','width=500,heigh...'); return false;"> California Proposition 65 </a>

I need this image in the pop-up, that if clicked, will take them to Califonia's website that has full information about Prop65. 

Cannot figure out how to do this. I know it is a ref, but how do I write it and where does it go?

Website: https://novatto.com/products/30-inch-bath-vanity-with-cafe-quartz-counter-nobv-30cm-6001 (click on the "Product Guide" tab. Last link in the tab, when clicked, initiates the pop-up.)

Thank you for any help/insight-