insert and retrieve an image in/from database

You can't store the image data in a 50 character string: if you can see the image, it just won't fit.
I also would not store the file path in a 50 character string - a file path can be a lot bigger than that! Make the field bigger, and store the path in it as a string.
The code is pretty much what I gave you last time, but without loading the file into a byte array first:

using (SqlConnection con = new SqlConnection(connectionString))
    {
    using (SqlCommand com = new SqlCommand("INSERT INTO tblAbc ([Image]) VALUES (@IM)", con))
        {
        com.Parameters.AddWithValue("@IM", "c:user\\abc\\desert.jpg");
        com.ExecuteNonQuery();
        }
    }