TexturePacker [-dupecheck] [--input DIRECTORY] [--output FILE.xbt]
Kodi uses a tool named TexturePacker to compile all images used in a skin into a single file. The benefit of it is that images inside the Textures.xbt will load faster in the skin. This is done by converting all images into a format that take less processing by Kodi when they need to be rendered onto the screen.
A common misconception is that TexturPacker will just compress the images into a single file. This if far from the truth, so don't be surprised if the Textures.xbt file is much larger than the total size of all the individual images.
The optional -dupecheck option is useful if you have included the same image multiple times in your media folder. For example, if your skin includes a lot of studio logos, most likely a lot of them are included multiple times but with a slightly different filename. The '-dupecheck' option will make sure each unique image is included only once in the Textures.xbt file, thus keeping the size of it as small as possible.
Check for image duplicates first
fully-qualified name of input directory with images
fully-qualified name of resulting compressed XBT file