Accessing image view from a different View Controller

Accessing image view from a different View Controller

I have two view controller classes along with two views in my storyboard
file. One is named ViewController and the other one is named
SettingsViewController because it's settings for the first view. I have a
UISwitch on the Settings view and I want it to change the image view that
is in the ViewController class. How can I access that from my Settings
class and change the image of the image view? I already tried importing
the ViewController class and synthesizing the image view but it says that
the image view must be declared in the ViewController class.