Zoom over images

Hi:

I used a zoom for a project and want to show it on my website.

I need to add this on the html:

<img id="zoom_05" src='images/girasoles-argentina-small.jpg' data-zoom-image="images/girasoles-argentina-large.jpg"/>

Where should I add the second part about data-zoom-image=.... Is it in the template?

Or shall I add it on an html module, and place the image in the folder in the server?

What if I want to apply the zoom to 3 images?

The zoom I'm using is called Elevate Zoom. http://www.elevateweb.co.uk/image-zoom/examples. I'm using the one with the lens.

Thanks.