Hi all!

I'm outlining an articles module for a CMS.
The content requires four levels in its hierarchy: categories, subcategories, articles and subarticles.
Each 'child' can relate to more than one 'parent'.
All articles in all levels can contain text and/or images.
An image can relate to more than one article.

Im no guru in database design, to say the least, having designed only for content that needed simple one-to-one relations.
It's the relations that I want to get right, so I left out the fields that aren't important.
I'd love some feedback on this sketch:
Code:
# Table articles
 
id - primary key
name
text
 
# Table images
 
id - primary key
name
 
# Table 'images_lookup'
 
article_id - primary key
image_id - primary key
 
# Table 'categories_lookup'
 
id - primary key, articles record with that id
 
# Table 'subcategories_lookup'
 
id - primary key, article record with that id
parent_id - primary key, 'category' articles record with that id
 
# Table 'articles_lookup'
 
id - primary key, article record with that id
parent_id - primary key, 'subcategory' articles record with that id
 
# Table 'subarticles_lookup'
 
id - primary key, article record with that id
parent_id - primary key, 'article' articles record with that id
Thanks!