I've found tons of character portraits available for download online. How do I import them into the game? It's probably obscenely simple, but I'm very computer illiterate.

It is all in your Readme file.

You download them, unzip them, and move to ...\Baldur's Gate\Portraits folder (it doesn't have to be the exact path). "Portraits" folder probably doesn't exist, so create it (case sensitive). Now, go to character record screen and select Customize->Appearance. Press "Custom" and select a portrait you like.

If you are creating a new character, just press Custom when choosing a portrait.

Well, I got ripped off. No read-me file. :) I do read them, when they're there.

Thank you, Vedran. I appreciate it.