A basic example of a drag and drop of an image into a panel
Code:
private void Form1_Load(object sender, EventArgs e)
  {
    panel1.AllowDrop = true;
    panel1.DragEnter += (o, xe) =>
    {
       if (xe.Data.GetDataPresent(DataFormats.FileDrop)) xe.Effect = DragDropEffects.Copy;
    };
    panel1.DragDrop += (o, se) =>
    {
      PictureBox p = new PictureBox();
      p.Size = panel1.Size;
      p.Image = Image.FromFile(((string[])se.Data.GetData(DataFormats.FileDrop))[0]);
      panel1.Controls.Add(p);
    };
  }