字节数组到IIS6上的图像

Question

REWORDING THE QUESTION:

I have a large number of .tif files, most of which (if not all) have the following definitions:

• Bit depth: 1
• Compression: CCITT T.6 (Group 4)

Some are multipage, some aren't.

I loaded them using the following:

private byte[] LoadArchivedFile()
{
    FileStream file = File.Open(fileAddress, FileMode.Open, FileAccess.Read, FileShare.Read);
    byte[] fileByteArray = ReadFully(file, 0);
    return fileByteArray;
}

I then saved these byte arrays in an SQL Server 12 DB, varbinary column.

Now, I am making an MVC2 web page to view these .tif files. The process is then supposed to be:

• load the byte array
• the convert it to Image
• select a page in the .tif
• convert that page to a Jpeg
• send the page to the browser

In the development environment everything works perfectly. Once I install the project on the target IIS (currently 6, I've opened a request for 7.5), the process fails on the following line:

[... load byte array from DB]
byte[] imageBinary = (byte[])results.fileBinary;

using(MemoryStream ms = new MemoryStream(imageBinary))
{
    Image image = Image.FromStream(ms);  <---- FAILS HERE
    [...]
}

The stacktrace:

System.ArgumentException: Parameter is not valid.
at System.Drawing.Image.FromStream(Stream stream, Boolean useEmbeddedColorManagement, Boolean validateImageData)
at System.Drawing.Image.FromStream(Stream stream)
at [MyCode]

Now, the byte array that I receive is not faulty - it is literally the same data from the DB. I even compared several bytes, overall length... anyway, it's the same source. This isn't where the fault lies.

I found another question with a similar (though not exactly the same) problem. There, the matter of bit depth, pixel format, compression and codecs. I am unsure at the moment what the pixel format of the original images is, though after conversion from byte array back to Image it is Format1bppIndexed.

I am pretty much at a loss... Is the problem with a missing codec on the target machine? Is there something I need to do before uploading the image binary to the DB?

Answer 1

FYI - if possible, a switch to IIS7 solves the problem completely.

I still haven't figured this out on IIS6... and spent another full workday hammering away at it... to no avail. I believe it to be something with MIME-type handling, some addition to a DLL in IIS7, maybe the GDI+... I don't really know. But, if anyone else runs into this problem - upgrade to IIS7 and save yourself the hassle.