The ornamental design for a pictureframecornercabinet, as shown and described.
FIG. 1 is a front, top and left-side perspective view of a picture frame corner cabinet embodying my new design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a right-side elevational view thereof;
FIG. 5 is a left-side elevational view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof; and,
FIG. 8 is a perspective view similar to FIG. 1, wherein a door is opened to reveal storage space for, for example, a fire extinguisher, the dotted line outline of a fire extinguisher forming no part of the design.