diff --git a/src/messages.c b/src/messages.c
--- a/src/messages.c
+++ b/src/messages.c
printf (" Resize/Scale output image by <zoomfactor>. Eg: \n");
printf (" 0.5 Shrink output to half of input \n");
printf (" 2.0 Magnify output to double the size \n");
+ printf (" Allowed range: 0.01 to 4.0 \n");
+ printf (" NOTE: Zooming will be carried out after all other \n");
+ printf (" operations, before writing out jpeg image \n");
printf (" Output will be written to <fits_file_root>.jpg. Wild card\n");
printf (" entries allowed in <fits_file>; For eg: *.fits, m31*.fits\n");
printf (" ngc???.fits etc. \n");