Oh Microsoft, you zany bunch of guys.  I was just sent one of your .MIX files and asked to convert it to a more common format.  My first question, what's an .MIX files?  Turns out it's an image format used by Microsoft Picture It.

Eerrm... ok.  There are literally hundreds of image formats already and you guys thought it would be a good idea to create another?  Your .MIX file must offer some revolutionary features which is no doubt widely supported in… Adobe Photoshop?  Nope.

Ok, well surely I don't have to buy Picture It?  No? because it doesn't exist?  Oh, you replaced it with Microsoft Digital Image, which I would need to buy.

Ok, well there is another Microsoft application that supports .MIX files, right? Microsoft Office Picture Manager? Nope.  Microsoft Word? Nope.  Let me do a search - it seems Microsoft Draw supports .MIX files, oh but it's discontinued.  But there is a replacement, right?  There is!?  Microsoft Photo Editor you say?  That's great!  Wait a minute – I have Microsoft Office 2003 and Microsoft Photo Editor isn't packaged with Office anymore.  Very funny.

Perhaps I'm not looking hard enough.  Someone must have had this same issue and found a single definitive way to convert your files.  Nope.  And here's a 17 page thread to prove it.

Way to create an image format that isn't supported by any of your own applications, Microsoft.  Zany guys.