CODEWITHSUNDEEP
.netexif
marc.d
marc.d

Reputation: 3844

Simple way to remove EXIF data from a JPEG with .NET

How can I remove all EXIF data from a JPEG image?

I found lots of examples on how to read and edit the EXIF data with various libraries, but all I would need is a simple example on how to remove it.

It is just for testing proposes, so even the ugliest and hackished approach would be helpful :)

I already tried searching for the EXIF start/end markers 0xFFE1 & 0xFFE2. The last one does not exist in my case.

Upvotes: 19

Views: 21659

Answers (5)

Tom Gullen
Tom Gullen

Reputation: 61727

Been a long time since this question but ran into an issue with this recently. These two functions will remove EXIF data from JPG's provided either as a filepath or byte[] array, without needing any third party packages.

internal static class ExifRemover
{
    internal static byte[] RemoveExifDataFromImage(string filePath)
    {
        using (var originalImage = Image.FromFile(filePath))
        {
            return Copy(originalImage);
        }
    }
    internal static byte[] RemoveExifDataFromImage(byte[] imageBytes)
    {
        using (var ms = new MemoryStream(imageBytes))
        using (var originalImage = Image.FromStream(ms))
        {
            return Copy(originalImage);
        }
    }
    private static byte[] Copy(Image originalImage)
    {
        using (var newImage = new Bitmap(originalImage.Width, originalImage.Height))
        using (var g = Graphics.FromImage(newImage))
        {
            g.DrawImage(originalImage, 0, 0, originalImage.Width, originalImage.Height);
            var b = new Bitmap(newImage);
            var converter = new ImageConverter();
            return (byte[])converter.ConvertTo(b, typeof(byte[]));
        }
    }
}

It works by copying the image to a new bitmap. With the returned byte array, you can call context.Response.BinaryWrite to write the image to the response.

Upvotes: 0

Mikael Svenson
Mikael Svenson

Reputation: 39695

I first wrote about this using WPF libs in my blog, but this sort of failed since Windows backend calls are a bit messed up.

My final solution is also much quicker which basically byte patches the jpeg in order to remove the exif. Fast and simple :)

[EDIT: Blog post has more updated code]

namespace ExifRemover
{
  public class JpegPatcher
  {
    public Stream PatchAwayExif(Stream inStream, Stream outStream)
    {
      byte[] jpegHeader = new byte[2];
      jpegHeader[0] = (byte) inStream.ReadByte();
      jpegHeader[1] = (byte) inStream.ReadByte();
      if (jpegHeader[0] == 0xff && jpegHeader[1] == 0xd8)
      {
        SkipExifSection(inStream);
      }

      outStream.Write(jpegHeader,0,2);

      int readCount;
      byte[] readBuffer = new byte[4096];
      while ((readCount = inStream.Read(readBuffer, 0, readBuffer.Length)) > 0)
        outStream.Write(readBuffer, 0, readCount);

      return outStream;
    }

    private void SkipExifSection(Stream inStream)
    {
      byte[] header = new byte[2];
      header[0] = (byte) inStream.ReadByte();
      header[1] = (byte) inStream.ReadByte();
      if (header[0] == 0xff && header[1] == 0xe1)
      {
        int exifLength = inStream.ReadByte();
        exifLength = exifLength << 8;
        exifLength |= inStream.ReadByte();

        for (int i = 0; i < exifLength - 2; i++)
        {
          inStream.ReadByte();
        }
      }
    }
  }
}

Upvotes: 28

RichieRich
RichieRich

Reputation: 3

It's too easy, use jhead.exe from here: http://www.sentex.net/~mwandel/jhead/

Make a little batch file if you want e.g.: jhead.exe -purejpg *.jpg

It will strip all metadata from all jpegs in the same folder.

Upvotes: -3

Nick
Nick

Reputation: 2575

what you should avoid is to decode and re-encode your images because this will hurt the quality. instead you should find a way to modify only the metadata. i haven't tried it but i think InPlaceBitmapMetadataWriter will do the trick.

Upvotes: 0

Dave Van den Eynde
Dave Van den Eynde

Reputation: 17405

I think reading in the file into a Bitmap object and writing out to a file again should do the trick.

I remember feeling frustrated while doing my "image rotation program" that it removed the EXIF data. But in this case, it's exactly what you want!

Upvotes: 5

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