NullReferenceExceptions

[GoogleCodeExporter]

I am getting a null reference exception after doing some manipulations (like 
flipping the image horizontally with my own code).

First, everything is OK and displayed successfully. After I do the operation on 
a rather large file (1024x768 JPEG), the error occurs (sorry, german only):

-------
Exception occurred: Der Objektverweis wurde nicht auf eine Objektinstanz 
festgelegt.,    bei Manina.Windows.Forms.ImageListViewItemCacheManager.DoWork() 
in 
C:\Ablage\ilv-svn\imagelistview-read-only\ImageListViewItemCacheManager.cs:Zeile
 232.
   bei System.Threading.ThreadHelper.ThreadStart_Context(Object state)
   bei System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   bei System.Threading.ThreadHelper.ThreadStart()
-------

So it seems that in line 232 of the file "ImageListViewItemCacheManager.cs" a 
null reference exception occures.

My code basically does:

--------
using (var img = Image.FromFile(item.FileName))
{
    img.RotateFlip(RotateFlipType.RotateNoneFlipX);
    img.Save(item.FileName);
}
--------

My assumption is that the background processing struggles when accessing the 
file that I have still in use or something like that.

Original issue reported on code.google.com by [email protected] on 6 Sep 2010 at 5:25