To redeem, not in a theological sense, is to recover; to regain possession of; to exchange. From this definition I think it is entirely possible for a painting to redeem. A painting can help us tap into our humanity. It can make us feel empathy; it can emit energy and feeling. A painting can bring about an exchange within our selves, a moment or many moments of reflection, and it can stimulate a dialogue with others.
I think inside his question is the idea that painting and looking at paintings is a way to be connected with our humanity. At its very best the language of images is a language of humanity; in all of their brutality as well as their beauty. Showing us what we have in common and what we share. A painting has the capacity to unite or to tear apart, a painting can allow us to see and feel the humane as well as the inhumane aspects of our world. Paintings can offer a glimpse into our selves; our ability for hatred, anger, greed, our capacity for violence as well as our capacity for kindness and compassion. A painting may offer us hope, may show us despair, and may share with us its joy. The viewer must be open as the artist must be open to receive what is not visible to the naked eye.