https://korithsmods.blogspot.com/p/tex-hammer.html
What is Tex Hammer?
Tex Hammer is a mod maker's tool for changing textures within Final Fantasy XI. Primarily aimed at making HD mods, Tex Hammer allows you to change the resolution of the game's various texture types with simple drag-and-drop functionality. It will also handle import and exporting. If you were familiar with TexTool, this is a more fully featured version of that.
Current Version: 1.2.1
- Please report bugs!
- Export button added
- Changed the UI significantly, including thumbnails for all the textures
Features include:
- View textures contained in a dat file
- Resize dxt3, palettes, and bump maps
- Import dxt3, palettes, and bump maps
- Export dxt3, palettes, and bump maps
- Search bar to filter through textures on large files
- Drag and drop support for opening dats and importing textures

A note about bump maps:
When importing a bump map, Tex Hammer will scan the file to see if the RGB channels are identical. If they are (or if it is a grey-scale image), it'll import the file as-is. If the RGB channels are NOT identical, it will convert the image into a grey-scale image and limit the range to #b5b5b5 to #fefefe (which is the range XI's original bump maps appear limited to).
Download Tex Hammer (Requires .net 4.6.1):
https://drive.google.com/open?id=1gIP3r ... JhM6_iSjwa
Not thoroughly tested, but also available for .net 3.5:
https://drive.google.com/open?id=1aIF8j ... Y36w7U2FVh
Changelog:
1.2.1
DXT3 exporting now has an option for full alpha or clamped alpha
Fixed a memory leak
1.2.0
UI Update. Now shows thumbnails of all the textures
Export feature
1.1.0
Added bump map support
1.0.0
Updated icon
RC 1
Public release