Most performant method to fetch just images from a collection

It was discussed in What's New in Photos APIs at WWDC that we should avoid using NSPredicate for custom fetch options if at all possible for performance purposes. In my app, I'm using NSPredicate to get only images from the user's library. I'm not seeing an API that would allow me to get assets from a specific collection filtered to just images without the use of NSPredicate though. Is there a more efficient way to perform this query that I'm not seeing?

let photoLibraryFetchResult = PHAssetCollection.fetchAssetCollections(with: .smartAlbum, subtype: .smartAlbumUserLibrary, options: nil)
let assetCollection = photoLibraryFetchResult.firstObject!

let fetchOptions = PHFetchOptions()
fetchOptions.predicate = NSPredicate(format: "mediaType = %d", PHAssetMediaType.image.rawValue)

let fetchResults = PHAsset.fetchAssets(in: assetCollection, options: fetchOptions)