Need a custom LibraryPicker with an initial image on a custom camera UII overlaymagePickerController iOS8

I am wondering how I can add a default library select button that can be found in the default iPhone camera app (can also be accessed through the control panel). The button looks like this, although this is the usual implementation of the application:

So, I know it can be done, but how? It is a library image collector where you can see taxis. I am using a fully customized UIImagePickerController with the imagePickerController property customOverlay

and I need to add this same button to my overlayView. If anyone can guide me to a solution that would be very helpful, thanks!

I can imagine using a button UIImagePickerControllerSourceTypePhotoLibrary

for a button and just setting the button property imageView

to the first image in the camera frame, but how would I go about doing that?

Also , this is somehow managed by default iOSUIImagePickerController