[NTG-context] [***SPAM***] File access for sourc, graphic, and pictures

I am just learning ConTeXt, so please bare with me. In all of the documentation that I've read so far, it shows the names of imported photographs, graphs, blocks, etc as a simple filename without any filename extensions or pathnames. Having a bunch of photographs anc charts files in the same directory as te tex files reallys clutters things up. I'd like to store photographs, etc., to use used in a subdirectory of the project. Also might be nice to have subdirectories for the sourc e of each part of a book. How do experienced people handle organizing files for large-ish scale projects such as a book? It would be educational to learn how this is handled. Thanks