dpi of the texture. If your base texture is 72dpi, you will reduce the size by half but at a dpi of 144. Its not always possible to do, so you do have to lookat the result, and if it doesn't fly, then simply cut down the size.

thou and I, my friend, can, in the most flunkey world, make, each of us, one non-flunkey, one hero, if we like: that will be two heroes to begin with. (Carlyle)