honestly i think it would be easier if you organized your updates into dated folders so you have a time sense of when you last updated and what happened when.
like 7-9-13 update [short blurb on what the update is]
in the folder would be everything regarding that update: post text, raw paint.net file, and exported .pngs
that way you have easy reference to old files and won't ever get lost.
and then have a separate folder for things you'll refer to often, like a 1-file character sheet containing everyone's character sprites, or rooms that you'll use multiple times (like a ship bridge, for outer rim)