This is a screenshot from unhacked vb2.3.0 (at least unhacked as far as attachments are concerned). As you can see you can delete the current attachment or change it with another attachment.

As a matter of fact apart from multi-attachment feature it is no different than VB3.
The attachment hack in vb.org was in preview post page. Due to the restrictions of Javascript, post preview page was losing the attachment and Chen applied a hack which saves the attachment in database to keep it in preview page too. There is a long discussion about the technical view of this hack in Site Feedback forum and if I recall correctly, Chen also released the hack in Full Releases section.