As far as I'm concerned, the poem is about the relationship between Aunt Jennifer and her husband. This poem puts emphasis on Aunt Jennifer's tigers because tigers she embroiders are symbols of what she desires to be like.
In the first stanza, I'm sure that "bright topaz denizens" the speaker refers to means Aunt Jennifer's tigers. "Bright" and "topaz" are adjectives not only colors of the animal's skin but also with good and positive meanings. Besides, the last two sentences shows that Aunt Jennifer wants to be like the fearless tigers.
In the second stanza, I'm in the opinion of that chances are that the speaker's aunt is a housewife worthy of the name, who is interested in embroidery. Or she is an artist by occupation. No matter what she is, one thing I can make sure is that she expresses her feelings and emotions through her works. In the last two sentences of the second stanza, we can see how hateful the speaker's Uncle is! Even if the wedding band is invisiable, it doesn't mean that the pressure Aunt Jennifer is brought upon is lighter. On the contrary, Aunt Jennifer may be more pressured because her husband trys to control her soul.
In the long run, in the first sentences of the last stanza, even if Aunt Jennifer is dead, she still can't got rid of her husband's control. I think the speaker must be sympathetic to Anut Jennifer because he or she sees her fright and scare. However, the work of art that she made stands for a kind of better life she dreams of, because of "prancing", "proud", and "unfraid".
After reading the poem, I also feel sympathy for the speaker's aunt. Owing that the poem generally talks about a poor woman and her attitude toward her tragic marriage, it occurs to me that many families in our society are the same as this situation. They don't lead a happy marriage life.There is no denying that most woman in our society are under the pressure their husbands give, inclusive of physical and mental violence. Although I don't know whether Aunt Jennifer is suffering from any violence or not. However, there is one thing I'm sure--She doesn't enjoy her life. Her husband makes her so small. Maybe he always gives order as if he were the king, or he usually strictly press Aunt Jennifer to do something she dislikes to do. A band is characteristic of a prisoner or a slave. And in my opinion, the speaker must dislike the way Uncle treats Aunt. In consequence, he or she wrote this poem to express his/her feelings toward the event. His purpose is to tell us, especially people married, that we shouled show respects to those around us.