My theories about that Tara Senapati painting from the 21st century 😛
Senapati spots the Dhruv-Tara photo with family, and to upstage it, orders the portrait to be made (even before the marriage actually takes place)
Sukku uses Dhruv's camera to take a photo of Tara and Senapati in one of the pre-marriage rituals. Either the King or Senapati himself see the photo, and get the idea to commission a portrait.
Dhruv comes disguised as a renowned painter to the court 😃, and makes the portrait with a dual intention- one to fulfill what he's already seen in the future, and two, to stop the wedding.