I have 2 queries :-

1. I want custom tags, something like the "new" tag/image to come up
based on certain criteria.
For example if I have use the WSS workflow, the tag should show if the
document is approved, rejected or pending.

2. I want to have a button in a document library based on which I want
I want to perform certain operations on the document. Do I have to
design a new web part for the same, or can the document library be
modified to have a button column.