The ornamental design for a family tree picture holder, substantially as shown and described.
FIG. 1 is a front elevational view of a family tree picture holder showing my new design;
FIG. 2 is a right side elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a top view thereof; and,
FIG. 5 is a bottom view thereof.