I claim the ornamental design for a digital still camera, as shown and described.
FIG. 1 is a top, rear and right side perspective view of a digital still camera showing my new design;
FIG. 2 is a bottom, rear and left side perspective view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a top view thereof;
FIG. 7 is a bottom view thereof; and,
FIG. 8 is an enlarged view of the portion indicated by lines 8-8 in FIG. 2.
The broken lines depict portions of the digital still camera in which the design is embodied that form no part of the claimed design. Additionally, the dash-dot lines denote the boundary of the claim and form no part of the claimed design.