Texture support was (possibly) fixed for BTX (and DDT support added) to the BAR extractor. Just drag a BAR file into the page and it’ll load up thumbnails for all images within. I’m using it to look through the Age of Mythology files; I dont have Age of Empires 3 installed, but it should work with that too.
Visit here to use the tool.
Weesals 
Could i download the converted ddt file in to bmp?
http://aoe3.heavengames.com/cgi-bin/forums/display.cgi?action=ct&f=14,39229,,10
or Like this photoshop plugin to open ddt files.