The painting is an it but the subject in the painting is a she.

I think you're going to get some funny looks if you called a female cartoon character or something an it. Which is what OP insisted we do

I think society has long established that we give inanimate objects and constructs gender. Bart Simpson is a he, despite being a cartoon voiced by a woman. He‘s often written by a woman, too, and the animation team will be mixed (although probably leaning male). Yet he remains a he in popular parlance.

Perhaps more akin to this situation, there’s a long tradition of referring to animated singers by the gender they present as. Gem & the Holograms are referred to as female, as are Josie & the Pussycats. Hatsune Miku - possibly the most direct comparison, being the first and most well-known “virtual singer” - is always a “she”. None of these are real people or based on real people.