Thanks for your question,
You can follow like bellow:
this.Controls.Add(new LiteralControl("<h3>Value: "));
ImageButton imgBtn= new ImageButton ();
imgBtn.Id="editRule";
imgBtn.ImageUrl = "~/images/edit.jpg";
this.Controls.Add(imgBtn);
this.Controls.Add(new LiteralControl("</h3>"));
Thanks,
Mamun