Question Regarding Textures

So I have been looking at Xarwarz's HD retextures for both games, and I noticed that the majority of them tend to be upside-down. Is there a reason for this? Do they need to be put into the Override folder upside-down? When I used KOTOR Tool to extract and look at the original textures they were rightside-up.

I can easily flip them and have been doing so. I just wonder why they're all inverted and what purpose it serves.

Thanks.