The ornamental design for an inflatablepillow-backed lounge float, as shown and described.
FIG. 1 is a front perspective view of an inflatable pillow-backed lounge float showing my new design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a left side elevational view thereof;
FIG. 5 is a right side elevational view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof; and,
FIG. 8 is another front perspective view thereof.
The speckling in the drawings depicts confetti-like objects that are visible through transparent surfaces and loosely carried within the interior of the inflatable pillow-backed lounge float. The broken lines in the drawings depict portions of the inflatable pillow-backed lounge float that form no part of the claimed design.