I finally decided to try the package the system with my home cooked templates.
One of the templates takes the path to an image as an argument. My problem is that all paths seems to be relative to the package folder rather than the .typ file to compile.
Is it possible to :
Supply a path relative to the path of the file to compile, or failing that,
Packages cannot access project files, unless the package is installed inside of the project
If you want to pass an image to your template, you will have to read it in your project and pass the image object to the template