python - Cannot identify image file ImageFieldFile -

i'm using django python, in models.py declared tournament model , attribute image, save method:

import datetime django.db import models django.utils import timezone tinymce.models import htmlfield rules.models import rule news.models import tag, news courts.models import court news.models import replace_spaces datetime import datetime sorl.thumbnail import imagefield, get_thumbnail pil import image django.core.files.storage import default_storage storage django.conf import settings  class tournament(models.model):     name = models.charfield(max_length=50, default='', verbose_name='nombre')     name_url = models.charfield(max_length=200, default='', editable=false)     inscription_opening_date = models.datefield('fecha de apertura de inscripcion')     inscription_closing_date = models.datefield('fecha de cierre de inscripcion')     tournament_starting_date = models.datefield('fecha de inicio del torneo')     tournament_ending_date = models.datefield('fecha de finalizacion del torneo')     description = htmlfield(default='', verbose_name='descripcion del torneo', blank=true)     image = imagefield(upload_to='tournamentpic', verbose_name='imagen')     situation = models.foreignkey(tournamentsituation, default='', verbose_name='estado del torneo')     tournament_format = models.foreignkey(tournamentformat, default='', verbose_name='formato del torneo')     regulation = models.foreignkey(rule, default='', verbose_name='reglamento')     tournament_type = models.foreignkey(tournamenttype, default='', verbose_name='tipo de torneo')     tournament_category = models.foreignkey(tournamentcategory, default='', verbose_name='categoria de torneo')     quota = models.integerfield(default=0, verbose_name='cupos')     tag = models.manytomanyfield(tag)     price = models.decimalfield(default=0, max_digits=6, decimal_places=2, blank=true)     zones = models.integerfield(default=0, verbose_name='zonas', blank=true)     knockout_opening_choices = (         ('64', 'ronda de 128'),         ('32', 'ronda de 64'),         ('16', 'ronda de 32'),         ('8', 'octavos de final'),         ('4', 'cuartos de final'),         ('2', 'semifinal'),     )     knockout_opening_round = models.charfield(max_length=2, verbose_name='instancia de inicio de llaves', choices=knockout_opening_choices, default='32', blank=true)     singles = models.integerfield(default=0, verbose_name='numero de singles', blank=true)     doubles = models.integerfield(default=0, verbose_name='numero de doubles', blank=true)     photo_full_size = models.charfield(max_length=255, blank=true, editable=false)    def save(self):     self.name_url = replace_spaces(self.name)     sizes = {'full': {'height': 415, 'width': 620},}      extension = self.image.name.rsplit('.', 1)[1]  # file extension     = datetime.now()     date = now.strftime("%h-%m-%s-%d-%m-%y")     self.image.name = date +'.png'     filename = date      super(tournament, self).save()     default_format = 'png'     im = image.open(self.image)      if extension not in ['jpg', 'jpeg', 'gif', 'png']: sys.exit()      new_size = im.resize((sizes['full']['width'], sizes['full']['height']), image.antialias)     medname = "-" + str(sizes['full']['width']) + "x" + str(sizes['full']['height']) + ".png"     thumb_path = upload_to + filename + medname     fh = storage.open(thumb_path, "w")     new_size.save(fh,default_format)     fh.close()     self.photo_full_size = thumb_path 

when save new tournament in admin, following error:

cannot identify image file <imagefieldfile: 16-16-58-19-06-2015.png> 

im uploading pictures , media files s3. strange thing in model, exact same configuration works perfectly! here other model:

from django.db import models tinymce.models import htmlfield datetime import datetime sorl.thumbnail import imagefield, get_thumbnail pil import image django.core.files.storage import default_storage storage django.conf import settings  import sys  media_url = getattr(settings, 'media_url')  upload_to = 'aboutpic/'  class name(models.model):     name = models.charfield(max_length=20, default='', verbose_name='nombre')     lastname = models.charfield(max_length=20, default='', verbose_name='apellido')      def __str__(self):                     return self.name + ' ' + self.lastname  class about(models.model):     image = imagefield(upload_to='aboutpic', verbose_name='imagen de portada')     introduction = htmlfield(default='', verbose_name='cuerpo de noticia', blank=true)     creation_date = models.datefield('fecha de publicacion', default=datetime.now(), editable=false)     names = models.manytomanyfield(name)     photo_full_size = models.charfield(max_length=255, blank=true, editable=false)      def save(self):         sizes = {'full': {'height': 415, 'width': 620},}          extension = self.image.name.rsplit('.', 1)[1]  # file extension         = datetime.now()         date = now.strftime("%h-%m-%s-%d-%m-%y")         self.image.name = date +'.png'         filename = date          super(about, self).save()         print self.image         default_format = 'png'         im = image.open(self.image)         if extension not in ['jpg', 'jpeg', 'gif', 'png']: sys.exit()          new_size = im.resize((sizes['full']['width'], sizes['full']['height']), image.antialias)         medname = "-" + str(sizes['full']['width']) + "x" + str(sizes['full']['height']) + ".png"         thumb_path = upload_to + filename + medname         fh = storage.open(thumb_path, "w")         new_size.save(fh,default_format)         fh.close()         self.photo_full_size = thumb_path          super(about, self).save()      def get_full_size(self):         return media_url + self.photo_full_size