Remove Hyperlink Underline on Images

Good afternoon,

I’ve decided to underline all my hyperlinks, however whenever I try to make an image linked it underlines the image. Whats the workaround for this? You can see an example on my site via the below url. The buy now button is underlined at the bottom of the page.

http://www.nateanglin.com/striiv-play-pedometer-unboxed-and-how-to-set-it-up/