We claim the ornamental design for a bag with folding frame, as shown and described.
FIG. 1 is a front perspective view of a bag with folding frame;
FIG. 2 is a top view thereof;
FIG. 3 is a right end view thereof;
FIG. 4 is a left end view thereof;
FIG. 5 is a front elevation view thereof;
FIG. 6 is a rear elevation view thereof; and,
FIG. 7 is a front perspective view thereof, with the broken line illustration of environmental structure in the drawing not part of the design sought to be patented.
The appearance of the underside surfaces, such as would in a bottom view, of the bag with folding frame, are not shown and are not claimed.