Okay. (I'm using the shorthand "ppi" to mean pixels per inch in what follows) Resolution is only meaningful when you express the pixel dimensions of an image with respect to an intended physical size. So, if I have an image which is 300 pixels square, then if printed at resolution of 300 ppi it will measure 1 inch along each side once printed, but the same image printed at 150 ppi it would measure 2 inches. The image has not changed of course, but the ratio of pixels to inch has and /that/ is the resolution. Upsampling from 72 to 300 ppi for the same expected print size will not produce a good quality image. Not even Photoshop can fix that. I'm not sure about the "I can't draw it again" bit. Why not just re-render at higher pixel dimensions? (Assuming this is an image sourced from Poser). I've probably misunderstood this :(