Store an Image efficiently in a XML file

Question

I currently writing a program that creates and fills Controls in a WPF application from a XML file. One of the features are that the User can choose a image he wants to display in the program. This image is displayed in a Image Control. After choosing the image, the program saves all data back to the XML file.

The image is converted and saved as follows:

byte[] bytes = new byte[1];
MemoryStream ms = new MemoryStream();
System.Drawing.Image image = new Bitmap(sPathOfImage);

image.Save(ms, System.Drawing.Imaging.ImageFormat.Bmp);
bytes = ms.ToArray();
XElement Image = new XElement("Image", Convert.ToBase64String(bytes));

xDocument.Add(Image);
xDocument.Save("xDocument.xml");

And this works perfectly, all's fine. However, main problem is the length of the value of the XElement Image. Even for 40kb images the lenght is 60,000 signs. And for a 9mb image it needs huge 13,200,000 signs. And now I'm looking for a way better solution to store images in the XML file.

Through specifications it has to be in one XML file.

So, is there a good way to make the string smaller, a more suitable stream, anything I'm missing out? Any hint is appreciated.

Answer 1

No magic will happen about filling an image content into XML file. The content will be proportional to the original file size. Even zipping the file and saving it to the XML will not help, because there are images with lower possibilities to be compressed. For evaluation purposes, I decided to find out how Visual Studio keeps the image in its resource file. The result is the following:

• VS puts the image under Resource folder
• in Resource.resx puts a reference to the image

..

  <data name="_myimage" type="System.Resources.ResXFileRef, System.Windows.Forms">
    <value>Resources\myimage.jpg;System.Drawing.Bitmap, System.Drawing, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a</value>
  </data>

Maybe would it make sense to stop reinventing the wheel, and believe the professionals? :)

Answer 2

To store image into XML file:

1. Read all the bytes into memory using File.ReadAllBytes().
2. Convert the bytes to a Base64 string using Convert.ToBase64String()
3. Write the Base64 Encoded string to your element content.

To retrieve the image from XML file:

 string val = currentXml.Element("image").Value; 
 byte[] bytes = Convert.FromBase64String(val); 
 MemoryStream mem = new MemoryStream(bytes); 
 Bitmap bmp2 = new Bitmap(mem);