Resize and save image while saving metadata

Question

I am trying to resize and save the image, which is quite simple (for example, see this example, the external example is no longer valid).

However, using this code, metadata information is removed from the image. I can’t imagine how to save metadata for a jpeg image.

** EDIT: Code Example **

public static void ResizeMethodThree(string sourceFile, string targetFile) { byte[] baSource = File.ReadAllBytes(sourceFile); PropertyItem[] propertyItems = new Bitmap(sourceFile).PropertyItems; using (Stream streamPhoto = new MemoryStream(baSource)) { BitmapFrame bfPhoto = ReadBitmapFrame(streamPhoto); BitmapMetadata metaData = (BitmapMetadata)bfPhoto.Metadata; int nNewPictureSize = 200; int nWidth = 0; int nHeight = 0; if (bfPhoto.Width > bfPhoto.Height) { nWidth = nNewPictureSize; nHeight = (int)(bfPhoto.Height * nNewPictureSize / bfPhoto.Width); } else { nHeight = nNewPictureSize; nWidth = (int)(bfPhoto.Width * nNewPictureSize / bfPhoto.Height); } BitmapFrame bfResize = ResizeHelper(bfPhoto, nWidth, nHeight, BitmapScalingMode.HighQuality); byte[] baResize = ToByteArray(bfResize); File.WriteAllBytes(targetFile, baResize); Image targetImage = new Bitmap(targetFile); foreach (var propertyItem in propertyItems) { targetImage.SetPropertyItem(propertyItem); } targetImage.Save(targetFile); } } public static BitmapFrame ResizeHelper(BitmapFrame photo, int width, int height, BitmapScalingMode scalingMode) { var group = new DrawingGroup(); RenderOptions.SetBitmapScalingMode( group, scalingMode); group.Children.Add( new ImageDrawing(photo, new Rect(0, 0, width, height))); var targetVisual = new DrawingVisual(); var targetContext = targetVisual.RenderOpen(); targetContext.DrawDrawing(group); var target = new RenderTargetBitmap( width, height, 96, 96, PixelFormats.Default); targetContext.Close(); target.Render(targetVisual); var targetFrame = BitmapFrame.Create(target); return targetFrame; } private static byte[] ToByteArray(BitmapFrame bfResize) { using (MemoryStream msStream = new MemoryStream()) { JpegBitmapEncoder jpgEncoder = new JpegBitmapEncoder(); jpgEncoder.Frames.Add(bfResize); jpgEncoder.Save(msStream); return msStream.ToArray(); } } private static BitmapFrame ReadBitmapFrame(Stream streamPhoto) { BitmapDecoder bdDecoder = BitmapDecoder.Create(streamPhoto, BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.None); return bdDecoder.Frames[0]; } 

Thanks, WTS

Answer 1

Use the Image.PropertyItems property on the source image to get a list of metadata elements. Scroll the list by calling Image.SetPropertyItem on the target image. Usually you should avoid resizing and recompressing the jpeg image when working from an uncompressed original, it is best to maintain quality and avoid artifacts.