The one thing that gets me is that it lacks "shape".  It feels too, two dimensional.  Even a simple rose would add a touch of color, plus a feeling of thickness.  Better yet would be a stuffed animal, vase of flowers or wreath.  Something that could give a feelign that the image was "thicker" than 2 inches.  I knwo it's a flat gravestone, but that's why it needs something to push you out some and give focus.

 

mdb