Yeah, the problem is 3rd party creators haven't follow any particular convention, using names or class, what-not, rather than following the original NWN pattern. Over the years, I've DL'ed hundreds of portraits, some from PW packs, some from DM'ed campaigns. Some of the collections off the Vault have had individual portraits renamed. Some folks rename a portrait to their PC name when they post them for campaigns. Thus, I have multiple copies of some popular portraits under different names.
One old, and rather dated, tool I do use to review and sometimes throw out incomplete or broken portraits is
NWN Spider. At one time you could use it to interface with the Vault and manage your portrait collection quite nicely. Unfortunately, that feature doesn't work anymore - probably due to changes on the Vault's end. Still a handy tool though for quickly browsing and seeing what you have collected though.
Karvon