Convert UIImage to NSData and convert back to UIImage in Swift

Question

I m trying to save a UIImage to NSData and then read the NSData back to a new UIImage in Swift  To convert the UIImage to NSData I m using the following code    let imageData  NSData   UIImagePNGRepresentation myImage    How do I convert imageData  i e   NSData  back to a new UIImage

User · Answer

Use imageWithData  method  which gets translated to Swift as UIImage data    let image   UIImage   UIImage data  imageData

User · Answer

Swift 5   let the image you create as UIImage be image  image pngData   as NSData

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For safe execution of code  use if-let block with Data to prevent app crash  amp    as function UIImagePNGRepresentation returns an optional value    if let img   UIImage named   TestImage png         if let data Data   UIImagePNGRepresentation img              Handle operations with data here                          Note  Data is Swift 3  class  Use Data instead of NSData with   Swift 3    Generic image operations  like png  amp  jpg both    if let img   UIImage named   TestImage png        UIImage named   TestImage jpg           if let data Data   UIImagePNGRepresentation img                   handleOperationWithData data  data                 else if let data Data   UIImageJPEGRepresentation img  1 0                   handleOperationWithData data  data                            func handleOperationWithData data  Data            Handle operations with data here         if let image   UIImage data  data               Use image               By using extension   extension UIImage        var pngRepresentationData  Data            return UIImagePNGRepresentation self             var jpegRepresentationData  Data            return UIImageJPEGRepresentation self  1 0                   if let img   UIImage named   TestImage png        UIImage named   TestImage jpg         if let data   img pngRepresentationData                 handleOperationWithData data  data               else if let data   img jpegRepresentationData                 handleOperationWithData data  data                         func handleOperationWithData data  Data            Handle operations with data here         if let image   UIImage data  data               Use image

User · Answer

Now in Swift 4 2 you can use pngData   new instance method of UIImage to get the data from the image   let profileImage   UIImage named  profile    let imageData   profileImage pngData

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Thanks  Helped me a lot  Converted to Swift 3 and worked  To save  let data   UIImagePNGRepresentation image   To load  let image   UIImage data  data

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Details   Xcode 10 2 1  10E1001   Swift 5   Solution 1  guard let image   UIImage named   img   else   return   let jpegData   image jpegData compressionQuality  1 0  let pngData   image pngData       Solution 2 1  extension UIImage       func toData  options  NSDictionary  type  CFString  - gt  Data            guard let cgImage   cgImage else   return nil           return autoreleasepool      - gt  Data  in             let data   NSMutableData               guard let imageDestination   CGImageDestinationCreateWithData data as CFMutableData  type  1  nil  else   return nil               CGImageDestinationAddImage imageDestination  cgImage  options              CGImageDestinationFinalize imageDestination              return data as Data                     Usage of solution 2 1     about properties  https   developer apple com documentation imageio 1464962-cgimagedestinationaddimage let options  NSDictionary             kCGImagePropertyOrientation  6      kCGImagePropertyHasAlpha  true      kCGImageDestinationLossyCompressionQuality  0 5       https   developer apple com documentation mobilecoreservices uttype uti image content types guard let data   image toData options  options  type  kUTTypeJPEG  else   return   let size   CGFloat data count  1000 0 1024 0 print    size  mb       Solution 2 2  extension UIImage        func toJpegData  compressionQuality  CGFloat  hasAlpha  Bool   true  orientation  Int   6  - gt  Data            guard cgImage    nil else   return nil           let options  NSDictionary                                                     kCGImagePropertyOrientation  orientation                                              kCGImagePropertyHasAlpha  hasAlpha                                              kCGImageDestinationLossyCompressionQuality  compressionQuality                                                   return toData options  options  type   jpeg             func toData  options  NSDictionary  type  ImageType  - gt  Data            guard cgImage    nil else   return nil           return toData options  options  type  type value               about properties  https   developer apple com documentation imageio 1464962-cgimagedestinationaddimage     func toData  options  NSDictionary  type  CFString  - gt  Data            guard let cgImage   cgImage else   return nil           return autoreleasepool      - gt  Data  in             let data   NSMutableData               guard let imageDestination   CGImageDestinationCreateWithData data as CFMutableData  type  1  nil  else   return nil               CGImageDestinationAddImage imageDestination  cgImage  options              CGImageDestinationFinalize imageDestination              return data as Data                         https   developer apple com documentation mobilecoreservices uttype uti image content types     enum ImageType           case image    abstract image data         case jpeg                          JPEG image         case jpeg2000                      JPEG-2000 image         case tiff                          TIFF image         case pict                          Quickdraw PICT format         case gif                           GIF image         case png                           PNG image         case quickTimeImage                QuickTime image format  OSType  qtif           case appleICNS                     Apple icon data         case bmp                           Windows bitmap         case ico                           Windows icon data         case rawImage                      base type for raw image data   raw          case scalableVectorGraphics        SVG image         case livePhoto                     Live Photo          var value  CFString               switch self               case  image  return kUTTypeImage             case  jpeg  return kUTTypeJPEG             case  jpeg2000  return kUTTypeJPEG2000             case  tiff  return kUTTypeTIFF             case  pict  return kUTTypePICT             case  gif  return kUTTypeGIF             case  png  return kUTTypePNG             case  quickTimeImage  return kUTTypeQuickTimeImage             case  appleICNS  return kUTTypeAppleICNS             case  bmp  return kUTTypeBMP             case  ico  return kUTTypeICO             case  rawImage  return kUTTypeRawImage             case  scalableVectorGraphics  return kUTTypeScalableVectorGraphics             case  livePhoto  return kUTTypeLivePhoto                                   Usage of solution 2 2  let compressionQuality  CGFloat   0 4 guard let data   image toJpegData compressionQuality  compressionQuality  else   return   printSize of  data   let options  NSDictionary                                             kCGImagePropertyHasAlpha  true                                      kCGImageDestinationLossyCompressionQuality  compressionQuality                                   guard let data2   image toData options  options  type   png  else   return   printSize of  data2         Problems   Image representing will take a lot of cpu and memory resources  So  in this case it is better to follow several rules   - do not run jpegData compressionQuality   on main queue  - run only one jpegData compressionQuality   simultaneously  Wrong   for i in 0   50       DispatchQueue global qos   utility  async           let quality   0 02   CGFloat i            let data   image toJpegData compressionQuality  quality          let data   image jpegData compressionQuality  quality          let size   CGFloat data  count  1000 0 1024 0         print    i   quality    quality     size rounded    mb             Right   let serialQueue   DispatchQueue label   queue   qos   utility  attributes      autoreleaseFrequency   workItem  target  nil   for i in 0   50       serialQueue async           let quality   0 02   CGFloat i            let data   image toJpegData compressionQuality  quality          let data   image jpegData compressionQuality  quality          let size   CGFloat data  count  1000 0 1024 0         print    i   quality    quality     size rounded    mb             Links   UTI Image Content Types CGImageDestinationAddImage       Thinking about Memory  Converting UIImage to Data in Swift Different resize technics

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UIImage data imageData scale 1 0  presuming the image s scale is 1   In swift 4 2  use below code for get Data     image pngData

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Image to Data -      if let img   UIImage named   xxx png             let pngdata   img pngData             if let img   UIImage named   xxx jpeg             let jpegdata   img jpegData compressionQuality  1          Data to Image -   let image   UIImage data  pngData

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To save as data   From StoryBoard  if you want to save  image  data on the imageView of MainStoryBoard  following codes will work   let image   UIImagePNGRepresentation imageView image   as NSData    To load  image  to imageView  Look at exclamation point          closely whether that is quite same as this one    imageView image   UIImage data  image as  Data     NSData  type is converted into  Data  type automatically during this process

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