The ornamental design for a photoholder, as shown and described.
FIG. 1 is a front elevation view of a photo holder showing my new design;
FIG. 2 is a rear elevation view;
FIG. 3 is a left elevation view;
FIG. 4 is a right elevation view;
FIG. 5 is a top plan view;
FIG. 6 is a bottom plan view; and,
FIG. 7 is an isometric view of a photo holder showing my new design.
The dotted lines shown in FIGS. 1 and 7 represent the outline of an exemplary photograph and form no basis of the claimed design. The dotted lines shown in FIG. 2 represent exemplary greetings and form no basis of the claimed design.