FIG. 1 is a front perspective view of a photo viewer showing our new design. FIG. 2 is a top plan view thereof. FIG. 3 is a front elevational view thereof. FIG. 4 is a left side view thereof. FIG. 5 is a right side view thereof. FIG. 6 is a rear elevational view thereof; and, FIG. 7 is a bottom view thereof.