itaysk

CQWP doesn't have a "file type" property in it's filter drop down. This is how you add it:

1. Insert a CQWP to a page and configure it as you would like.
2. Export the web part and save it as ".webpart" file on your local computer.
3. Open the ".webpart" file in a text editor. (I use SharePoint Designer)
4. Look for the following line:
   <property name="CommonViewFields" type="string" />
5. Replace it with the following line:
   <property name="CommonViewFields" type="string">DocIcon,Lookup</property>
   This will make the CQWP retrieve also the DocIcon field that basically include the file extention.
6. Look for the following line:
   <property name="AdditionalFilterFields" type="Lookup" null="true" />
7. Replace it with the following line:
   <property name="AdditionalFilterFields" type="Lookup" >DocIcon</property>
   This will make our CQWP to allow you to filter by our newly added DocIcon field through the filtering UI in the web part's toolpane.
8. Save the file.
9. Go to a sharepoint page and import the modified ".webpart" file into your page.