Did you learn anything from my answer to your first question:
How Do I Save One Image Of All Picturebox Controls Which Added In My Pictrebox?
I think Sergey is right: this is one case you should not try and work with the PictureBox Control; please review Sergey's answer(s), and the links he provided.
A "PictureBox" Control is a container for
one image. That image should be assigned to the PictureBox using the 'Image property of the PictureBox, or the ImageLocation property.
The fact you can add Controls to the PictureBox's ControlCollection ... a facility PictureBox inherits since its ancestor is the Control Class ... does not mean you
should use it to host multiple other PictureBoxes ... or any other Control.
Use a Panel, or other ContainerControl Control, which allows multiple PictureBoxes, or other Controls, to be added to its ControlsCollection.
Before posting your next question, please do search CodeProject for articles on images, and image manipulation: there are many excellent resources here.