I have a UICollectionView which is about the size of the screen. The UICollectionViewCells that it displays are the same size as the collectionView. Each cell has a UIImage which is the size of the cell. The CollectionView has paging enabled so essentially it is a full screen photo slideshow that the user can swipe through.
The problem is that
-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
Are you sure you're not accidentally overriding
- (void)collectionView:(UICollectionView *)collectionView didDeselectItemAtIndexPath:(NSIndexPath *)indexPath? "Select" vs. "deselect" has tripped me up in the past with Xcode's code completion.