ceci est un exemple de Sql Server
connection.Open();
SqlCommand command1 = new SqlCommand("select imgfile from myimages where [email protected]", connection);
SqlParameter myparam = command1.Parameters.Add("@param", SqlDbType.NVarChar, 30);
myparam.Value = txtimgname.Text;
byte[] img = (byte[])command1.ExecuteScalar();
MemoryStream str = new MemoryStream();
str.Write(img, 0, img.Length);
Bitmap bit = new Bitmap(str);
connection.Close();
regarde icihttp://www.akadia.com/services/dotnet_read_write_blob.html