Find your Toribash directory (normally on C: \Games\), there will be a folder in there called "custom", create a new folder inside this one, you can name it whatever you want (eg: Preview etc.).
Put your .tga files inside this new folder with the proper name of the part you want to texture. This are the names the files should have:



Now go to Toribash, start a new singleplayer game, press enter to open the text box and type:
/lp 0 preview
This will load the .tga items in the "Preview" folder you created inside "custom"

If you want Uke to wear the textures instead of Tori, type
/lp 1 preview