The ornamental design for a stylized window insert for a garage door, as shown and described.
FIG. 1 is an enlarged front, elevational view of a left side panel of the window insert of the invention;
FIG. 2 is an enlarged right side view of the window insert of FIG. 1, the left side view being the reverse image thereof;
FIG. 3 is an enlarged bottom view of the window insert of FIG. 1, the top view being the reverse image thereof;
FIG. 4 is an enlarged front elevational view of a right side panel of the window insert of the invention; and,
FIG. 5 is a perspective view of the window inserts of FIGS. 1 and 4 in place on a garage door, the garage being shown in phantom lines and not forming a part of the invention.