如何从sql server将图像加载到转发器控件中

如何从sql server将图像从sql数据库加载到图像控件中？图像以图像格式存储。。。图像控制在中继器中中继器中的代码

<table id="tableposts" style="text-align: center; width: 100%; height: 80%;">
    <tr>
        <td>
            <asp:LinkButton ID="lbpostusername" runat="server" 
                Text='<%#Eval("UserName") %>'>
            </asp:LinkButton>
        </td>
    </tr>
    <tr>
        <td>
            <asp:Label ID="posthead" runat="server" 
                Text='<%#Eval("PostHead") %>'></asp:Label>
        </td>
    </tr>
    <tr>
        <td>
            <p id="postcontent"><%#Eval("PostContent") %></p>
        </td>
    </tr>
    <tr>
        <td>
            <asp:Image ID="postimage" runat="server" ImageUrl=""/>
        </td>
    </tr>
</table>

检索值的代码

private DataSet GetData()
{
    SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["LoginConString"].ConnectionString);
    SqlDataAdapter da = new SqlDataAdapter("Select PostID,UserName,PostHead,PostContent,PostImage from Posts WHERE USERID ='" + Session["New"].ToString() + "'", con);
    DataSet ds = new DataSet();
    da.Fill(ds);
    postids = ds.Tables[0].Rows[0].ToString();
    return ds;
}

public string GetImageFromByte(object byt)
 {
   byte[] byts = (byte[])byt;
   return byteArrayToImage(byts);
 }

   public string GetImageFromByte(object byt)
      {
         byte[] byts = Convert.ToByte(byt);
         return byteArrayToImage(byts);
      }