In reference to the ImageUrl
parameter in the following code:
<asp:ImageMap ID="CheckoutMap" runat="server" ImageUrl="(!~/App_Themes/skin_(!SKINID!)/images/step_2.gif!)">
<asp:RectangleHotSpot Bottom="54" HotSpotMode="Navigate" NavigateUrl="~/shoppingcart.aspx?resetlinkback=1&checkout=true"
Right="87" />
</asp:ImageMap>
They are skin tokens specific to ASP Dot Net Storefront. Here is a link to the manual - http://manual.aspdotnetstorefront.com/p-489-skin-tokens.aspx