I suggest this.

[hebaek76916]

More Instagram like,
YPLibraryVC+CollectionView.swift

`

func deselect(indexPath: IndexPath) {

    if let positionIndex = selection.firstIndex(where: {
		$0.assetIdentifier == mediaManager.fetchResult[indexPath.row].localIdentifier
	}) {

        selection.remove(at: positionIndex)
        // Refresh the numbers
        var selectedIndexPaths = [IndexPath]()
        mediaManager.fetchResult.enumerateObjects { [unowned self] (asset, index, _) in
            if self.selection.contains(where: { $0.assetIdentifier == asset.localIdentifier }) {
                selectedIndexPaths.append(IndexPath(row: index, section: 0))
            }
        }
        v.collectionView.reloadItems(at: selectedIndexPaths)
        
        var selectionLastIndex: IndexPath?
        if selection.count != 0 { // 🕊 ~
            let last = selection.last!.index
            selectionLastIndex = IndexPath(row: last, section: 0)
            v.collectionView.deselectItem(at: indexPath, animated: false)
            v.collectionView.selectItem(at: selectionLastIndex, animated: false, scrollPosition: [])
            currentlySelectedIndex = selectionLastIndex!.row
            changeAsset(mediaManager.fetchResult[selectionLastIndex!.row]) //  ~🕊
        } else { // 🕊
     
            // Replace the current selected image with the previously selected one
            if let previouslySelectedIndexPath = selectedIndexPaths.last {
                v.collectionView.deselectItem(at: indexPath, animated: false)
                v.collectionView.selectItem(at: previouslySelectedIndexPath, animated: false, scrollPosition: [])
                currentlySelectedIndex = previouslySelectedIndexPath.row
                changeAsset(mediaManager.fetchResult[previouslySelectedIndexPath.row])
            }
        } // 🕊
        checkLimit()
    }
}

`

I think when deselect, move to selection's last index is more make sense.

How about my opinion?..

[NikKovIos]

For now it act like in instagram when you select or deselect in multiple selection mode.