I am rich in rare Halsins. I came to Baldur's Gate 3's master portrait artist, Oskar Fevras, hoping for a new headshot to use on half-orc LinkedIn, or maybe a cute wallet-type deal of my Baldur's Gate beau. But Oskar only has eyes for Halsin—I had everyone in my party talk to the NPC, and he just painted Halsin.
In the late game conclusion to the quest, Free the Artist, you're supposed to get that portrait as a quest reward. I'm not sure if you were only intended to get one, but you can speak to Oskar separately as the various members of your party and get the dialogue to paint a new portrait each time.
There's no rhyme or reason to who he paints though: the first time, I had two different characters talk to him and each got a portrait of the cheeky wizard of Waterdeep, Gale. I had to investigate further.
I decided to cycle every companion at my camp in and out of my party to get the maximum Oskar exposure, one portrait for each of my companions plus my Dark Urge avatar. I just cranked through the same dialogue over and over: "you're a hero, let me paint you, oh what should we title the painting?" that sort of thing. Notably, you can't tell what these portraits will look like just sitting in your inventory—the only way to inspect one is to drop it on the ground.
I banked up my nine paintings and sought out some choice lighting in central Baldur's Gate to lay my cards on the table. First results were disappointing: just a field of nine blank canvases. Something didn't feel right about this, so I did a quicksave-quickload like I'd just failed a Persuasion check.
Oops! All Halsins. I was greeted by a field of Halsins smugly mugging at me from a spread of perfectly square canvases I'd laid out before the city's gallows.
On a subsequent reload, though, it was Jaheira in my strange new monitor bank, and the mechanics of the portraits started to come into focus. Oskar seems to just randomly select a member of your currently active party as his subject, and my coworker, Sean Martin, was able to nab a headshot of his avatar by losing the party and going in solo.
Unfortunately, this isn't a permanent fix. From what I can tell, Oskar's magical portraits refresh to a random member of your currently active party every time you load a save—I checked back on my shrine to Halsin from a later save and it had turned into a Karlach fiesta.
All that being said, I'm not sure I ever want to see this fixed—I love my weird field of haunted portraits defacing Baldur's Gate's execution grounds. Whatever joy I may have gotten from having a little headshot of my half-orc like he was an up-and-coming actor recently arrived in LA pales in comparison to the quizzical surprise of getting double Gales, and then my perverse glee at seeing all nine Halsins laid out like that.