(defun rsc (/ img base_pt ref_pt1 ref_pt2 new_pt)
  (princ "\nSelect image to scale by reference: ")
  (if (setq img (car (entsel)))
    (progn
      (princ "\nSpecify base point: ")
      (if (setq base_pt (getpoint))
        (progn
          (princ "\nSpecify first point of reference length: ")
          (if (setq ref_pt1 (getpoint))
            (progn
              (princ "\nSpecify second point of reference length: ")
              (if (setq ref_pt2 (getpoint ref_pt1))
                (progn
                  (princ "\nSpecify new length: ")
                  (if (setq new_pt (getpoint ref_pt2))
                    (progn
                      ; Start the SCALE command with the selected image
                      (command "SCALE" img "" base_pt "R" ref_pt1 ref_pt2 new_pt)
                      (princ "\nImage scaled by reference successfully.")
                    )
                    (princ "\nNo new length point specified.")
                  )
                )
                (princ "\nNo second reference point specified.")
              )
            )
            (princ "\nNo first reference point specified.")
          )
        )
        (princ "\nNo base point specified.")
      )
    )
    (princ "\nNo image selected.")
  )
  (princ)
)