Unable to cast object of type System.String to type System.B

Question

I am passing data from one page to another page, but one image this exception is being raised that

 

Unable to cast object of type System.String to type System.Byte.

 

here is my second page html of image..

<asp:TemplateField HeaderText="Image">
<ItemTemplate>
<%--<asp:Image ID="img" runat="server" ImageUrl='<%# Eval("Data").ToString() %>' Height="100px" Width="100px" />--%>
<asp:Image ID="Data" runat="server" Width="100px" Height="80px" ImageUrl='<%# "data:image/jpg;base64," + Convert.ToBase64String((byte[])Eval("Data")) %>' />
</ItemTemplate>