UIImagePickerController within existing UIPopoverController resizing issue on iPad - xcode

Question

I am working on an iPad app where I have a button that generates a popover controller that I am populating with a specific view controller. Here is the button code that generates the UIPopoverController and loads it with a specific view (signUpListAddEditViewController):
-(void)addSignUpList:(id)sender {
signUpListAddEditViewController = [[SignUpListAddEditViewController alloc] init];
popover = [[UIPopoverController alloc] initWithContentViewController:signUpListAddEditViewController];
popover.popoverContentSize = signUpListAddEditViewController.view.frame.size;
[popover presentPopoverFromBarButtonItem:sender permittedArrowDirections:UIPopoverArrowDirectionUp animated:YES];
signUpListAddEditViewController.popover = popover;
}
Inside SignUpListAddEditViewController.m, I have several fields and a tableview. One of the fields is a UIButton where I display an image and allow the user to load a new image using this button. Since I am already in a popover, I swap the content controller with the UIImagePickerController. So far, so good.
-(void)takePicture:(id)sender
{
UIImagePickerController *imagePicker = [[UIImagePickerController alloc] init];
[imagePicker setSourceType:UIImagePickerControllerSourceTypePhotoLibrary];
[popover setPopoverContentSize:popupScreenSize animated:YES]; // popupScreenSize is a CGSIZE set to 500 x 900
[popover setContentViewController:imagePicker animated:YES];
}
The view is swapped out with the imagePicker with the size remaining the same as the original view and I can see the various picture galleries (Camera Roll, Photo Stream, etc). Here is where it gets strange. As soon as I pick one of the galleries, the view is replaced with a thumbnail view of the pictures in that gallery AND THEN the view resizes to a much narrower width. The images are distorted and nearly impossible to select one of them.
I have tried setting [popover setPopoverContentSize:CGSIZE animated:YES] prior to every access to the popover controller, with everything resizing properly EXCEPT the detailed image view? Any ideas where I can override the thumbnail image gallery view?
Here is the code for the didFinishPickingMediaWithInfo method where I again override the content size:
-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
UIImage *image = [info objectForKey:UIImagePickerControllerOriginalImage];
[thisList setThumbnailDataFromImage:image];
[popover setPopoverContentSize:popupScreenSize animated:YES];
[popover setContentViewController:self animated:YES];
listImageButton.imageView.image = image;
}