title: Pillow changing the RGB value of a picture does not work
body: <p>I am trying to scale the rgb value of a image.</p>
  <p>The way I learnt is by doing <code>getpixel</code> and <code>putpixel</code> for every pixel.</p>
  <pre><code>import PIL
  from PIL import Image
  from PIL import ImageEnhance
  from PIL import ImageFont,ImageDraw
  
  # read image and convert to RGB
  image=Image.open(&quot;readonly/msi_recruitment.gif&quot;)
  image=image.convert('RGB')
  
  # build a list of 9 images which have different brightnesses
  images=[]
  intensity = [0.1, 0.5, 0.9]
  channel=[0,1,2] 
  
  for c in channel:
      for i in intensity:
          newImage = PIL.Image.new(image.mode, (image.width, image.height+100))
          newImage.paste(image,(0,0))
          
          text=&quot;channel {} intensity {}&quot;.format(c, i)
          font = ImageFont.truetype(r'readonly/fanwood-webfont.ttf', 75)  
          Draw=ImageDraw.Draw(newImage)
          Draw.text((10,470), text, fill=&quot;white&quot;, font=font, align=&quot;left&quot;)
          
          
          for row in range(image.height):
              for col in range(image.width):
                  p = image.getpixel((col, row)) # p as RGB pixel values
                  
                  if channel == 0:
                      newImage.putpixel((col, row), (int(p[0]*i),p[1],p[2]))
                  elif channel == 1:
                      newImage.putpixel((col, row), (p[0],int(p[1]*i),p[2]))    
                  elif channel == 2:
                      newImage.putpixel((col, row), (p[0],p[1],int(p[2]*i)))    
          
          images.append(newImage)
  
  </code></pre>
  <p>However, It did not work, the pixels' RGB did not change.</p>
  <ol>
  <li><p>What is wrong with my codes?</p>
  </li>
  <li><p>Is there a way to scale the RGB values of a picture as a whole instead of looping through pixel by pixel?</p>
  </li>
  </ol>