DownSizeImage.swift

  func downsample(imageURL: URL, to pointSize: CGSize, scale: CGFloat) -> UIImage {
        let imgeSourceOptions = [kCGImageSourceShouldCache: false] as CFDictionary
        let imageSource = CGImageSourceCreateWithURL(imageURL as CFURL, imgeSourceOptions)!
        
        let maxDimensionInPixel = max(pointSize.width, pointSize.height) * scale
        let downsampleOptions = [
            kCGImageSourceCreateThumbnailFromImageAlways: true,
            kCGImageSourceShouldCacheImmediately: true,
            kCGImageSourceCreateThumbnailWithTransform: true,
            kCGImageSourceThumbnailMaxPixelSize: maxDimensionInPixel
        ] as CFDictionary
        
        let downsampledImage = CGImageSourceCreateThumbnailAtIndex(imageSource, 0, downsampleOptions)!
        return UIImage(cgImage: downsampledImage)
    }
    
    let image = self?.downsample(imageURL: filename, to: CGSize(width: 50, height: 50), scale: 1)