Image.Save () throws an ExternalException for the image loaded from Stream (Image.FromStream ())

Question

I am tracking an unpleasant problem, and I narrowed down the problem and realized that this happens when I deal with the Image instance returned by Image.FromStream (). I have a utility method that returns an instance of an image from a file using Stream, so I don't have an open file descriptor. Here is this useful method (nothing special):

public static Image ImageFromFileReleaseHandle(string filename) { using (FileStream fs = new FileStream(filename, FileMode.Open, FileAccess.Read)) { return Image.FromStream(fs); } } 

When I try to save an image loaded from the above method, I get InteropServices.ExternalException "A general error occurred in GDI +". The following code example will demonstrate this:

 private void button6_Click(object sender, EventArgs e) { var filename = @"D:\My Documents\My Pictures\2010-03-27 hangover hike.jpg"; // Get an Image instance Image image; using (FileStream fs = new FileStream(filename, FileMode.Open, FileAccess.Read)) { image = Image.FromStream(fs); } // Save to a temp file - this is the code that throws the exception image.Save(Path.GetTempFileName()); } 

If I upload an image using Image.FromFile (), I can save without problems:

 private void button6_Click(object sender, EventArgs e) { var filename = @"D:\My Documents\My Pictures\2010-03-27 hangover hike.jpg"; // Get an Image instance Image image = Image.FromFile(filename); // Save to a temp file - this is the code that throws the exception image.Save(Path.GetTempFileName()); } 

I can not come up with any additional information that would be useful. I hope my code examples are simple enough so you can clearly see the problem.

Thanks Steve

Answer 1

try this instead

 // Get an Image instance Image image; using (FileStream fs = new FileStream(filename, FileMode.Open, FileAccess.Read)) { image = Image.FromStream(fs); // Save to a temp file - this is the code that throws the exception image.Save(Path.GetTempFileName()); } 

I think the block used is giving you problems

Answer 2

According to the documentation :

You must leave the stream open for the life of the image.

Try calling “Save” inside the use block to make sure that no exception is thrown if the stream is still open.

Answer 3

Based on the suggestions and comments so far and my own additional reading, I think I have a working solution. Basically the problem is that I cannot close the Stream. Great, but I also can't leave FileStream open without a guarantee that it will close properly.

Instead, I read the file into the buffer, and then create a MemoryStream and pass it to Image.FromStream ().

 var filename = @"D:\My Documents\My Pictures\2010-03-27 hangover hike.jpg"; byte[] imageData = FileUtils.ReadWholeFileBytes(filename); Image image = Image.FromStream(new MemoryStream(imageData)); // dump the buffer to test if this upsets the Memory Stream. I need to read more // about MemoryStream and how it may keep the GC from cleaning up it underlying data imageData = null; // Save to a temp file image.Save(Path.GetTempFileName()); 

Thank you all for your suggestions and questions.

Answer 4

I have the same problem, but instead of using FileStream , I only have a MemoryStream , because I am loading an image from a database. When I save the image for the first time in the database, everything is fine, but when I update the image in the database, it throws an ExternalException . Here is my code if you want to analyze.

 public class ImageConverter { public static byte[] imageToByteArray(Image imageIn) { if (imageIn == null) return new byte[] { 45 }; using (MemoryStream ms = new MemoryStream()) { imageIn.Save(ms, imageIn.RawFormat); return ms.ToArray(); } } public static Image byteArrayToImage(byte[] byteArrayIn) { if (byteArrayIn == null) return null; using (MemoryStream ms = new MemoryStream(byteArrayIn)) { Image returnImage = Image.FromStream(ms); return returnImage; } } }