Write NSImage to disk

NSImageDisk.swift

extension NSImage {
    func writeToFile(file: String, atomically: Bool, usingType type: NSBitmapImageFileType) -> Bool {
        let properties = [NSImageCompressionFactor: 1.0]
        guard
            let imageData = TIFFRepresentation,
            imageRep = NSBitmapImageRep(data: imageData),
            fileData = imageRep.representationUsingType(type, properties: properties) else {
                return false
        }
        return fileData.writeToFile(file, atomically: atomically)
    }
}

Usage:

let filePath = ...
someImage.writeToFile(filePath, atomically: true, usingType: .NSPNGFileType) // as png
someImage.writeToFile(filePath, atomically: true, usingType: .NSJPEGFileType) // as jpg