In the Instagram profile of Estefania Puerta, a visual artist with strong ties to Vermont, she asks, "How am I not my selfie?" It's a funny and layered question, and it speaks to the complicated process of defining oneself and others through portraiture — particularly in the hyper-fast pace of the digital era. For Middlebury College Museum of Art director Richard Saunders, though, the selfie phenomenon is but the latest chapter within a monumental tradition. Years in the making and now on view, "American Faces: A Cultural History of Portraiture and Identity" traces the myriad forms and uses of portraiture specifically in the United States. It incorporates more than 90 objects, from stately oil paintings of wealthy European colonists to a Fathead decal of LeBron James — and nearly everything in between. What quickly becomes clear is that this most intimate type of image contains enough insight into the workings of history and power to induce vertigo. Luckily, Saunders has sorted his "rudimentary taxonomy of portraiture," as he calls it in exhibition text, into broad thematic categories. The exhibition comes in conjunction with Saunders' newly published, image-laden book of the same name. Both are divided into seven categories: "The Rich," "Portraits for Everyone," "Fame," "Propaganda," "Self and Audience," "Rituals, Power, and Memory" and "The Gallery." From its outset in the so-called New World, portraiture was inextricably linked to money, class and power. From the 1700s to the 1850s, we learn, the vast majority of successful artists were commissioned to do "society paintings." In a pre-photography era, this practice was a primary way to commit one's likeness to history — though certainly not always accurately. A medium-size oil painting of 19th-century stage actress Charlotte Saunders Cushman is hung next to a daguerreotype of her; in the former she appears very youthful, rosy-cheeked and full of life. In the photo, she is plain and severe. While arguably all personal portraiture demonstrates a certain wish to immortalize oneself, many of the works on view within "Rituals, Power, and Memory" address death and memorialization head-on. Among the most striking examples are seven small post-mortem photographs — a practice that was once commonplace. In Edwin Romanzo Elmer's 1890 painting "Mourning Picture," the artist realistically depicts his young daughter, who had died months earlier, in front of his and his wife's home with some of the girl's favorite things. Saunders presents public forms of…