XML - Immagini cifrate?

<?xml version="1.0" encoding="ISO-8859-1" ?>  
   <xmlarchive generator="..." created="###">
      <fileset>
         <file>
            <filename>immagine.png</filename>
            <content>iVBORw0KGgoAAAANSUhEUgAAAAoAAAAKCAYAAACNMs+9AAAABGdBTUEAANbY
              1E9YMgAAABl0RVh0U29mdHdhcmUAQWRvYmUgSW1hZ2VSZWFkeXHJZ
              TwAAAA/SURBVHjaYmRgEhjIAIABBATA5EAIICIVggQQEQrBAggohUCBBDR
              CgECiGiFAAFEtEKAACJaIUAAEa0QIMAAs2IAetPOw3cAAAAASUVORK5CYII=
             </content> 
             <path /> 
             <binary>1</binary>
          </file>
          ...

89504E470D0A1A0A0000000D494844520000000A0000000A08060
000008D32CFBD0000000467414D410000D6D8D44F583200000019
74455874536F6674776172650041646F626520496D616765526561
647971C9653C0000003F4944415478DA6264606048632002000410
1303910020808856081040442B040820A215020410D10A01028868
85000144B4428000225A21400011AD1020C000B362007AD3CEC377
0000000049454E44AE426082

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 XmlDocument xml = new XmlDocument();
            xml.Load(@"D:\temp\file.xml");

            //Seleziono il primo nodo per fare una prova
            XmlNode el = xml.SelectSingleNode("xmlarchive/fileset/file/content");

            if (el != null)
            {
                byte[] arr = Convert.FromBase64String(el.InnerXml);
                File.WriteAllBytes(@"d:\temp\image.gif", arr);
            }

‰PNG


IHDR

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union conv
{
        unsigned int l;
        struct bytes
        {
                char b1;
                char b2;
                char b3;
                char b4;
        } b;
};

char convert (char c)
{
        if (c == 63)
                return 47;
        else if (c == 62)
                return 43;
        else if (c >= 52)
                return c - 4;
        else if (c >= 26)
                return c + 71;
        else
                return c + 65;
}

unsigned int toBase64(char b1, char b2, char b3)
{
        conv src, dest;
        src.b.b1 = b3;
        src.b.b2 = b2;
        src.b.b3 = b1;
        src.b.b4 = 0;
        //conv.l == b4 b3 b2 b1
        dest.b.b1 = convert(src.b.b1 & 0x3f);
        src.l = src.l >> 6;
        dest.b.b2 = convert(src.b.b1 & 0x3f);
        src.l = src.l >> 6;
        dest.b.b3 = convert(src.b.b1 & 0x3f);
        src.l = src.l >> 6;
        dest.b.b4 = convert(src.b.b1 & 0x3f);

        return dest.l;
}