+.B \-pan \fIseconds\fP
+How long each pan should last. Default 6 seconds.
+.TP 8
+.B \-fade \fIseconds\fP
+How long each fade (in and out) should last. Default 2 seconds.
+If set to 0, then no cross-fading will be done (all transitions
+will be jump-cuts.)
+
+Note that fades are included in the pan, so \fI\-pan\fP should
+always be longer than \fI\-fade\fP (it is auto-corrected if not.)
+.TP 8
+.B \-zoom \fInumber\fP
+Amount to zoom and pan as a percentage. Default: 75, meaning that
+75% or more of each image will always be visible. If set to 100%,
+then the images will always fill the screen, and no panning or
+zooming will occur. Images will still smoothly fade from one
+to another, however, assuming \fI\-fade\fP is non-zero.