How do you add a pinterest pin it button that works to a Muse site? Pin it yielding empty box w/ ?

Hey! I'd like to add the Pin It pinterest button to my Muse sites using the Pin It html provided by Pinterest. However, when I use the Pin it button I placed near an image, Pinterest comes up but I get an empty white box with a question mark.  There is no image to pin. What am I doing wrong? Please help.

Thanks,

Rachel