collectionViewLayout sizeForItemAtIndexPath makes the view look blank - objective-c

Question

I´m trying to implement a CollectionViewController, where the images sizes are shown correctly. But when I implement the method "collectionViewLayout sizeForItemAtIndexPath", none of the images are shown. Does anybody know why? Here is my CollectionViewController code:
#import "PhotosViewController1.h"
#interface PhotosViewController1 ()
#end
#implementation PhotosViewController1
- (void)viewDidLoad
{
[super viewDidLoad];
_carImages = [#[#"Wild-Love.jpg",
#"d919004663f99c934b20c1bd46fcad3e.jpg",
#"164_v-viergalerie.jpg"] mutableCopy];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#pragma mark -
#pragma mark UICollectionViewDataSource
-(NSInteger)numberOfSectionsInCollectionView:
(UICollectionView *)collectionView
{
return 1;
}
-(NSInteger)collectionView:(UICollectionView *)collectionView
numberOfItemsInSection:(NSInteger)section
{
return _carImages.count;
}
-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView
cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
PhotosCell *myCell = [collectionView
dequeueReusableCellWithReuseIdentifier:#"MyCell"
forIndexPath:indexPath];
UIImage *image;
int row = [indexPath row];
image = [UIImage imageNamed:_carImages[row]];
myCell.imageView.image = image;
return myCell;
}
#pragma mark -
#pragma mark UICollectionViewFlowLayoutDelegate
-(CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
{
UIImage *image;
int row = [indexPath row];
image = [UIImage imageNamed:_carImages[row]];
return image.size;
}
#end