How to check that an uploaded file is a valid Image in Django

Also, you should use verify() as follows:

from PIL import Image
im = Image.open(model.file)
im.verify()

Good news, you don't need to do this:

class ImageField(upload_to=None, height_field=None, width_field=None, max_length=100, **options)

Inherits all attributes and methods from FileField, but also validates that the uploaded object is a valid image.

https://docs.djangoproject.com/en/1.10/ref/models/fields/#django.db.models.ImageField