You should do something like this:
<asp:gridview id="GridView1" runat="server" autogeneratecolumns="False" xmlns:asp="#unknown">
<columns>
<asp:templatefield>
<itemtemplate>
<img src="<%# GetImageUrl(Eval("FullName1")) %>" />
</itemtemplate>
</asp:templatefield>
</columns>
<columns>
<asp:templatefield>
<itemtemplate>
<img src="<%# GetImageUrl(Eval("FullName2")) %>" />
</itemtemplate>
</asp:templatefield>
</columns>
<columns>
<asp:templatefield>
<itemtemplate>
<img src="<%# GetImageUrl(Eval("FullName3")) %>" />
</itemtemplate>
</asp:templatefield>
</columns>
</asp:gridview>
With a class behind that contains the names FullName1 etc...