Scaling div size with background image whilst keeping aspect ratio

The easiest way is to use below style for the div

<div class="divImage" style='<%# "background: url(\"" + DataBinder.Eval(Container.DataItem, "divImage") + "\") no-repeat center center; background-size: cover;" %>'></div>

A more detailed approach is listed in this post

http://stackoverflow.com/questions/15883157/is-it-possible-to-make-a-responsive-div-with-a-background-image-that-maintains-t