آرایه ش که اینطور میشه
PictureBox[] diceloc = new PictureBox[] {pic1, pic2, pic3, pic4};
اینم کد تولید picturebox
PictureBox[] Shapes = new PictureBox[Num_Picbox];
for (int i = 0; i < Num_Picbox; i++)
{
Shapes[i] = new PictureBox();
Shapes[i].Name = "ItemNum_" + i.ToString();
Shapes[i].Location = new Point(label5.Left+1,label5.Top);
Shapes[i].Size = new Size(100, 100);
Shapes[i].BackColor = Color.Black;
Shapes[i].Image = (Bitmap)(e.Data.GetData(DataFormats.Bitmap));
Shapes[i].Visible = true;
this.Controls.Add(Shapes[i]);
}