You have uploaded the picture as .TIF in Sap using ABAP RSTXLDMC and have also add the statement
/: INCLUDE ZHEX-SAMPLE-PICTURE OBJECT TEXT ID ST LANGUAGE EN
in your SapScript but the problem is that in print preview it's not displaying the picture.
It is normal that the picture doesn't show in print preview and you will be able to see the object only after printing.
Don't let this bother you as long as the picture is shown on the hardcopy printout.