I understand about layers, alpha channels, etc. Let me try to explain further. You buy a prim skirt that comes with the base skirt and the actual prim skirt right? The base has a pattern/design/texture that matches the prim skirt. I want to add a pattern to the base skirt psd before uploading it because otherwise I will not be able to texture it in-world since the template will be placed in the fabric area of the pants. I apologize if I am not being clear.