Some help with schema

[Sean Funk]

I'm looking to store several different bits of data in two separate tables. The data will be inserted by a Spring batch.

In one table, I'm store a bunch of data about a forum post. In the second table, I'm storing any images that were embedded in the post. Not every post has an image, and multiple posts might link to the same image, so my thinking was this:

In the main table, I would store all the post information, and in the postImage column, this would be a comma separated value (is that a good idea) of zero to many identifiers, that are then unique indexes to the blobs in the second table. Is this correct thinking or is it bad juju to have multiple identifiers in a single field? How would you handle arbitrary numbers of reference items for a given row, in that case?

I'm new to building schemas and I'm trying to read as much on the subject as possible - but I feel like I'm at a bit of a standstill until I can get some validation of my work thus far.