-.B \-draw \fInum\fP\fP
-Specifies the draw method. 0 = wireframe, 1 = solid, 2 = light (default), 3 = checker texture mapped, 4 = PNM image is read from stdin and mapped to the surface
+.B \-mode \fImode\fP\fP
+Specifies the draw method: wireframe; solid (meaning a solid colored
+surface); light (same as solid, but with lighting effects);
+checker (a texture-mapped checkerboard pattern); or grab (meaning
+grab an image to manipulate.)
+
+When grabbing images, the image will be grabbed from the portion of
+the screen underlying the window, or from the system's video input,
+or from a random file on disk, as indicated by
+the \fIgrabDesktopImages\fP, \fIgrabVideoFrames\fP,
+and \fIchooseRandomImages\fP options in the \fI~/.xscreensaver\fP
+file; see
+.BR xscreensaver-demo (1)
+for more details.