code:

if 'file' in request.FILES:
                        file = request.FILES['file']
                try:
                        img = Image.open(StringIO(request.FILES['photo']['content']))
                        request.FILES['file']['dimensions'] = img.size
                except:
                        request.FILES['file']['error'] = True
                content_type = file.get('content-type')
                if len(file['content']) > 1024 * 750:
                        raise forms.ValidationError('nein kiddo')
                if content_type:
                        main, sub = content_type.split('/')
                        if not (main == 'image' and sub in ['jpeg','gif','png']):
                                raise forms.ValidationError('wrong file type')
                filename = file['filename']