What's the best approach on sourcing value from item (type: image) on to the transaction line items? Netsuite currently has a limitation (and enhancement filed) for creating image type column line fields.

Adding image lines on fields sounds like you're doing something wrong - especially if it comes from the item record. what is it you are trying to accomplish?

I'm basically trying to get the item image from the item/assembly record on to a transaction so that it can be used for advanced pdf/html template for emails

I would be more tempted to use a custom link field instead - then you can use some logic to get it into the vieable link on your PDF

Thanks