Raylpdf problem- CDF-PDF

Hello, I want calculate pdf and cdf with Rayl function in matlab. But i think result isn't correct. Please view my result.

clc
clear all
close all

   I = imread('cameraman.tif');
  im = imhist(I);
  p = raylpdf(im,.6);
  sump = sum(p);
  pcdf = raylcdf(im,.6);
  figure;
  plot(I,p);