gistfile1.txt

private func downscaleImageData(_ data: Data, maxPixelSize: CGFloat = 800) -> UIImage? {
    guard let source = CGImageSourceCreateWithData(data as CFData, nil) else {
        return nil
    }

    let properties = CGImageSourceCopyPropertiesAtIndex(source, 0, nil) as? [CFString: Any]
    let exifOrientationRaw = properties?[kCGImagePropertyOrientation] as? UInt32
    let uiOrientation = exifOrientationRaw.flatMap { UIImage.Orientation(rawValue: Int($0)) } ?? .up

    let options: [NSString: Any] = [
        kCGImageSourceShouldCache: false,
        kCGImageSourceCreateThumbnailFromImageAlways: true,
        kCGImageSourceThumbnailMaxPixelSize: maxPixelSize
    ]

    guard let cgImage = CGImageSourceCreateThumbnailAtIndex(source, 0, options as CFDictionary) else {
        return nil
    }

    return UIImage(cgImage: cgImage, scale: 1.0, orientation: uiOrientation)
}