default image if null in sql

i'm trying to load a default image if it reutrns null

<ahref="<%# Eval("url_img","uploads/images/{0}") %>"rel="lightbox[on]"title="+<a target='_self' href='detalhe_atleta.aspx?id=<%# Eval("ida") %>'>Info</a>"><imgsrc='<%# Eval("url_img","uploads/images/{0}") %>'/></a>