title: Django Save Image on different model fields
body: <p>I have a model called Picture . When an image is uploaded into this model , it will automatically be re-size before saving.</p>
  
  <p>My main goal is to re-size the uploaded image into 2 separate images . So I can use it for different purpose like small picture , and big pictures . So what I done to achieve this goal is create another field called small . which represents small pictures .</p>
  
  <p>I have 2 functions underneath my model called save and small . These functions will automatically re-size the image.</p>
  
  <p>My plan is , when I upload an image to the model . My save function will automically resize the image and save it into images folder but how can I also get my small function to grab that image from image field so it can resize it and save it into my small field.</p>
  
  <p>To sum is all up , it's just retrieveing an upload image and resizes the image on both field.</p>
  
  <pre><code>class Picture(models.Model):
      user = models.ForeignKey(User)
      small = models.ImageField(upload_to="small/",blank=True,null=True)
      image = models.ImageField(upload_to="images/",blank=True)
  
      def save(self , force_insert=False,force_update=False):
          super (Picture,self).save(force_insert,force_update)
  
          pw = self.image.width
          ph = self.image.height
          mw = 500
          mh = 500
  
          if (pw &gt; mw) or (ph &gt; mh):
              filename = str(self.image.path)
              imageObj = img.open(filename)
              ratio = 1
  
              if ( pw &gt; mw):
                  ratio = mw / float(pw)
                  pw = mw
                  ph = int(math.floor(float(ph)* ratio))
              if ( ph &gt; mh):
                  ratio = ratio * ( mh /float(ph))
                  ph = mh 
                  pw = int(math.floor(float(ph)* ratio))
  
              imageObj = imageObj.resize((pw,ph),img.ANTIALIAS)
              imageObj.save(filename)
  
      def save(self , force_insert=False,force_update=False):
          super (Picture,self).save(force_insert,force_update)
  
          pw = self.image.width
          ph = self.image.height
          mw = 300
          mh = 300
  
          if (pw &gt; mw) or (ph &gt; mh):
              filename = str(self.image.path)
              imageObj = img.open(filename)
              ratio = 1
  
              if ( pw &gt; mw):
                  ratio = mw / float(pw)
                  pw = mw
                  ph = int(math.floor(float(ph)* ratio))
              if ( ph &gt; mh):
                  ratio = ratio * ( mh /float(ph))
                  ph = mh 
                  pw = int(math.floor(float(ph)* ratio))
  
              imageObj = imageObj.resize((pw,ph),img.ANTIALIAS)
              imageObj.save(filename)
  </code></pre>
  
  <p>If this doesn't make sense , alert me so I can modify it</p>