how to access private members

How can I access picturebox created dynamically as a private member in function1, in the click event of the menuitem of the context menu.

for eg: if I have a picturebox created at runtime and if that picturebox also has a conetxt menu attached to it programatically and the menu looks like rotate and flip.

click on rotate should rotate picturebox, but my problem is
I am not able to access the picturebox from the click event of rotate_ctxmnuitm as the sender object in this click event is the parent (ie., context menu object itself) and picturebox is private in some other function.