How do I add a "size guide" link to a specific active attribute?

I have around 4000 products in my shop. In the clothing dept., I need to add a link next to the drop down size attribute that will take my customer to an image showing the clothes size for bust, waist and hip measurement.
I have the dropdown size attribute in place, and need to add the extra link to that image showing the code for those measurements. Can someone tell me how to write this link and how to put it in place so the link only returns the size guide on, for example, the coats, and not on the shoes that are in the same database.Thanks in advance.

It is possible to add COMMENTS against an attribute (in the COMMENTS field).

If you go to your option names manager, and then select the attribute to EDIT (buttons on the right hand side), a new screen comes up with a COMMENTS field.

You can type in a hyperlink to your size chart, and if you are skilled enough, you can make this a POPUP, so the chart floats above your main page. The field is limited to 64 characters, so if you need more space, you will have to alter the field's VARCHAR value in the database, through phpMyAdmin.

Thank you.