是的，这对我也很重要。这就是我所做的。

模型：

from app.storage import OverwriteStorage

class Thing(models.Model):
    image = models.ImageField(max_length=SOME_CONST, storage=OverwriteStorage(), upload_to=image_path)

还定义在models.py中：

def image_path(instance, filename):
    return os.path.join('some_dir', str(instance.some_identifier), 'filename.ext')

在另一个文件中，storage.py：

from django.core.files.storage import FileSystemStorage
from django.conf import settings
import os

class OverwriteStorage(FileSystemStorage):

    def get_available_name(self, name):
        """Returns a filename that's free on the target storage system, and
        available for new content to be written to.

        Found at http://djangosnippets.org/snippets/976/

        This file storage solves overwrite on upload problem. Another
        proposed solution was to override the save method on the model
        like so (from https://code.djangoproject.com/ticket/11663):

        def save(self, *args, **kwargs):
            try:
                this = MyModelName.objects.get(id=self.id)
                if this.MyImageFieldName != self.MyImageFieldName:
                    this.MyImageFieldName.delete()
            except: pass
            super(MyModelName, self).save(*args, **kwargs)
        """
        # If the filename already exists, remove it as if it was a true file system
        if self.exists(name):
            os.remove(os.path.join(settings.MEDIA_ROOT, name))
        return name

显然，这些是这里的示例值，但是总体而言，这对我来说效果很好，并且根据需要进行修改应该非常简单。