Picture frame

FIG. 1 shows a front perspective view of an ornamental design for a picture frame according to the invention;

FIG. 2 shows a rear perspective view of an ornamental design for a picture frame according to the invention;

FIG. 3 shows a front plan view of an ornamental design for a picture frame according to the invention;

FIG. 4 shows a top plan view of an ornamental design for a picture frame according to the invention;

FIG. 5 shows a rear plan view of an ornamental design for a picture frame according to the invention;

FIG. 6 shows a side plan view of an ornamental design for a picture frame according to the invention;

FIG. 7 shows a bottom plan view of an ornamental design for a picture frame according to the invention;

FIG. 8 shows a plan view of an inside portion of an ornamental design for a picture frame according to the invention taken from line 8--8 in FIG. 5;

FIG. 9 shows a first cross sectional view of an ornamental design for a picture frame according to the invention taken from line 9--9 in FIG. 3; and,

FIG. 10 shows a second cross sectional view of an ornamental design for a picture frame according to the invention taken from line 10--10 in FIG. 3.

The broken lines are for environmental purposes only and form no part of the claimed design.