access any contols of the mdiparent form into its child form

Suppose that Form1 is your MDI parent form and that it contains a panel called panel1.

Suupose also that this panel contains a picturebox called pictureBox1 and that you want to access its Image property from a child form. Then you can do so as follows:

Form1 f1 = (Form1)this.MdiParent;

Panel p1 = (Panel)f1.Controls["panel1"];

PictureBox pb1 = (PictureBox)p1.Controls["pictureBox1"];

Image img = pb1.Image;

Code for accessing other controls on the MDI parent form follows similar lines.