List<PictureBox> pictureBoxes = new List<PictureBox>();
pictureBoxes.add(pictureBox1);
pictureBoxes.add(pictureBox2);
pictureBoxes.add(pictureBox3);
pictureBoxes.add(pictureBox4);
pictureBoxes.add(pictureBox5);
Dictionary<PictureBox, Label> labelsLinkedToPictureBoxes = new Dictionary<PictureBox, Label>();
lablesLinkedToPictureBoxes.Add(pictureBox1, label1);
lablesLinkedToPictureBoxes.Add(pictureBox2, label2);
lablesLinkedToPictureBoxes.Add(pictureBox3, label4);