I am using Magnific Popup for my gallery. When you click on a thumbnail, it popups the image. I am trying to add a "Download image" button inside the popup. I have the HTML snippet displaying fine, but the href of the download link needs to be populated with the img url.

Here is the JS code:

```
markup: '<div class="mfp-figure">'+
                '<div class="mfp-close"></div>'+
                '<div class="download-img"><a href="#">Download image</a></div>'+
                '<figure>'+
                    '<div class="mfp-img"></div>'+
                    '<figcaption>'+
                        '<div class="mfp-bottom-bar">'+
                            '<div class="mfp-title"></div>'+
                            '<div class="mfp-counter"></div>'+
                        '</div>'+
                    '</figcaption>'+
                '</figure>'+
            '</div>',

```

How do I put the image src variable in the anchor's href?