试试
byte [] b = (byte[])dataSet1.Tables["DrawPic"].Rows[0]["ContentPic"];
System.IO.MemoryStream stream = new System.IO.MemoryStream(b);
Bitmap bm = new Bitmap(stream);
byte [] b = (byte[])dataSet1.Tables["DrawPic"].Rows[0]["ContentPic"];
System.IO.MemoryStream stream = new System.IO.MemoryStream(b);
Bitmap bm = new Bitmap(stream);
String sFileName = (String)dataSet1.Tables["DrawPic"].Rows[0]["ContentPic"];
Bitmap bm = new Bitmap(sFileName); //if you are using ASP.NET, change to Server.MapPath(sFileName);