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Lots of crashes - because of course NWN is ancient and sometimes hates things. Things noted here:
DDS flippy flip
The DDS → TGA in crunch does not flip the file. This means when doing (intermediary upscaled PNG) → DDS you do the opposite of your other textures. The results need to be "upside down" when the DDS file is viewed. It causes some wild issues otherwise, of course!
Distort TXI option
Distorted textures cannot exceed 256x256 resolution apparently - needs fully testing since one "shinywater" below is bigger than 256 already 
This is the TXI option "distort 1". This means primarily water but also other things like lava! Also look out for "arturowidth" and "arturoheight"
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