I normally like to write code myself instead of installing some large script just to do one task for me. There were a few scripts out there that could create thumbnails, but I wanted something simple because I knew that I wouldn’t use most of those features. Additionally, I wanted an excuse to use the Python Image Library with Django 1.0 and to learn how to take an uploaded picture and create a few thumbnails of them.
After searching for a while I was able to piece some things together to get something working. In my model I added these two functions.
def thumbnailed(self, file, width, height): try: size = width, height tmp_file = StringIO() im = Image.open(StringIO(file.read())) im.thumbnail(size, Image.ANTIALIAS) im.save(tmp_file, im.format) except IOError: return None return ContentFile(tmp_file.getvalue())
Using StringIO, I was able to create a temporary file in memory to hold the thumbnail data and return it where it would later be passed to Django. I was trying to create 3 thumbnails which presented another problem: Django was obliterating the uploaded file and the data in my temp files when I was saving. So I figured out how to get around that, but there may be better ways.
def create_thumbnails(self, file): pic = self.thumbnailed(file, 160, 400) if pic is not None: self.picture.save(file.name, pic, save=False) # file is annihilated by django, use self . picture now thumb = self.thumbnailed(self.picture, 288, 96) if thumb is not None: self.thumbnail.save(file.name, thumb, save=False) tiny = self.thumbnailed(self.thumbnail, 144, 48) if tiny is not None: self.tiny_image.save(file.name, tiny, save=False)
The model has picture, thumbnail, and tiny_image as ImageFields and create_thumbnails, which was originally called from the view and passed the uploaded file from request.FILES.
There was a lot of trial and error trying to get this together, so I hope it helps someone skp past that.