ASP.NET C# How to enlarge GridView DataBound imageField picture when hoverover?

I am doing school work and need some help, I want the image in a 'Relevant Information' ImageField column that is DataBound to be enlarged when hoverover. Here are my codes:

    <div style="height:200px; width: 610px; overflow: auto;">
                <asp:GridView ID="GV_insView" runat="server"
            AutoGenerateColumns="False"
            CssClass="Grid" AlteatingRowStyle-CssClass="alt" Width="511px">
<AlteatingRowStyle CssClass="alt"></AlteatingRowStyle>
            <Columns>
                <asp:BoundField HeaderText="Customer ID" DataField="NRIC" />
                <asp:BoundField HeaderText="Insurance Type" DataField="insType" />
                <asp:BoundField HeaderText="Date Filed" DataField="dateFiled" DataFormatString="{0:dd/MM/yyyy}"/>
            <asp:ImageField HeaderText="Relevant Information" DataImageUrlField="relInfo" ControlStyle-Width="100" ControlStyle-Height="100"> 
              </asp:ImageField>
            </Columns>
        </asp:gridview>
                    </div>