How to Draw Shape (use Class) on picturebox And Save it ?

How to Draw Shape (use Class) on picturebox And Save it ?
I could write a program
but
Can not be Saved the shape Are created  by Class
And
when I draw a new shape,Previous Shapes are removed?
Project file Link For Download:
http://msiamian.persiangig.com/Project/TestPaint2.rar

please Help Me;