What would cause my Silverlight .xap to quadruple in size suddenly?

I've been working on a Silverlight application. I just noticed that the .xap file is now four times as big as it was, what could have caused that?

Here's some other info:

• there seems to now be many more language settings in the bin/Release dire开发者_如何学Goctory
• I checked "Reduce size of .xap" in under Properties/Silverlight but that just brought it down from 1300 to 1200.
• I reference the System.Windows.Controls.Toolkit dll but I was doing that even when it was 325K

Screenshot of build directories before and after:

_{(source: deviantsart.com)}

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Since .xap is just a zip file, rename the .xap file to .zip and open it up and take a look at the files contained. Perhaps you added a large resource inadvertently?