iOS: Getting image size without downloading

ImageIO+ImageSize.swift

import ImageIO

func imageSize(with url: NSURL) -> CGSize {
    
    var size: CGSize = .zero
    let source = CGImageSourceCreateWithURL(url, nil)!
    let options = [kCGImageSourceShouldCache as String: false]
    if let properties = CGImageSourceCopyPropertiesAtIndex(source, 0, options as CFDictionary?)  {
        
        if let properties = properties as? [String: Any],
            let width = properties[kCGImagePropertyPixelWidth as String] as? Int,
            let height = properties[kCGImagePropertyPixelHeight as String] as? Int {
            size = CGSize(width: width, height: height)
        }
    }
    
    return size
}