Download/install a painting program. Dont use the default paint.
Draw up a shirt/face make sure its centered and not crappy.
Save it, make a thumb for it. Basically rezise the image and save it in a different folder so you can keep both as the same name.
Make a folder named thumbs and place the smaller version of the decal/face in it.
Put the larger decal/face near the thumbs folder.
Highlight(click, drag.) both thumbs folder and large image.
Right click, send to - compressed folder(Its possible on Windows IDK if you have a mac...)
Name face zips Face_[face name], and name decals Decal_[decal name]
Upload to a fileshare website and add link into a new topic on BL forums.
It may be long but its worth reading. Its what I do when I make decals and it works fine.
Normal face/decal should be sized 256x256.
Thumbs should be 64x64.
