You will need Tile Molester Mod:
Now open "WM1.PIM.tim" or "WM1.TIM" (they are exactly the same file)
4 BPP linear, reverse order
160 x 32 tiles
Use this black and white palette:
You will see something like this:
By the way, there are some texts in the bottom left corner of this file.
Do the same thing when you open the other files (WM2.PIM.tim or WM2.TIM). You will get this file:
And that is all you need to know regarding these files.