how to set image to height 100% in specific width in google chrome with CSS?

how to set image to height 100% in specific width in google chrome with CSS?

I wrote this css (below), and works properly in firefox, but when I use
Chrome, the problem happened, the chrome assumed that "height : 100%" is
tobe 100% of the real image. I want it 100% just from the width that I've
set.
.prof-img{ width:150px; height:100%; }