Love this painting! (But please correct the title, it's Ahasuerus)
I'm sorry, I'm not available yet. Even this image is an old drawing which I posted in order to post at least something.
While the white woman is larger indeed, I'd say the characters, with their similar and rhyming poses, are shown as equal to each other. I don't see a colonial discourse here (at least, it's far from the worst examples of the colonial discourse).