您可以添加一个可空的文件字段来存储缩略图，并在save方法中手动填充或使用模型保存信号。
您可以使用这些问题的答案来了解如何生成这些缩略图：
https://stackoverflow.com/a/1843043/1823497
https://stackoverflow.com/a/27565893/1823497
由于生成缩略图可能是一项耗时的工作，我建议使用celery task在后台完成，而不会阻塞您的Web服务器。

1)安装opencv-python 2）检查文件是视频还是图像3）我不知道从内存中视频捕获，所以将文件写入磁盘，然后使用cv2.videocapture加载4）取第一帧并写入磁盘5）再次从磁盘加载图像并保存在数据库6）删除磁盘中的临时文件

import mimetypes
import cv2
from django.core.files import File
from django.core.files.storage import default_storage
from django.core.files.base import ContentFile
from pathlib import Path

    

    new_story=Story(user=user, file=file)
    file_type, t =mimetypes.guess_type(str(file))
    
    if file_type.split('/')[0] == "image":
        new_story.save() 
        return Storymutation(story=new_story)
    path = default_storage.save('video.mp4', ContentFile(file.read()))
    vidcap = cv2.VideoCapture(f"./media/{path}")
    success,image = vidcap.read()
    cv2.imwrite(f"./media/{path}.jpeg", image)
    thumbnail = default_storage.open(f"{path}.jpeg")
    new_story.thumbnail=thumbnail
    new_story.save()
    thumbnail.close()
    del image, vidcap
    default_storage.delete(path)
    default_storage.delete(f"{path}.jpeg")
    return Storymutation(story=new_story)

这里是一个生成缩略图的例子。你可以根据Django项目的需要调整代码。
我用的是ffmpeg-python: Python bindings for FFmpeg

import ffmpeg

from django.core.files.base import ContentFile
from django.core.files.temp import NamedTemporaryFile

with NamedTemporaryFile() as temp_video_file:
    # user_video is a django model instance with video and thumbnail FileFields
    in_memory_file = user_video.video

    if in_memory_file.multiple_chunks():
        for chunk in in_memory_file.chunks():
            temp_video_file.write(chunk)
    else:
        temp_video_file.write(in_memory_file.read())

    try:
        probe = ffmpeg.probe(temp_video_file.name)
        time = float(probe["streams"][0]["duration"]) // 2
        width = probe["streams"][0]["width"]

        with NamedTemporaryFile(suffix=".jpg") as temp_thumbnail_file:
            (
                ffmpeg.input(temp_video_file.name, ss=time)
                .filter("scale", width, -1)
                .output(temp_thumbnail_file.name, vframes=1)
                .overwrite_output()
                .run(capture_stdout=True, capture_stderr=True)
            )

    except ffmpeg.Error as e:
        # do whatever you want with the error
        error = e.stderr.decode()
    else:
        # you can also just return the thumbnail e.g
        # return ContentFile('name_you_like.jpg', temp_thumbnail_file.read())
        user_video.thumbnail.save(
            Path(temp_thumbnail_file.name).name,
            ContentFile(temp_thumbnail_file.read()),
            save=True,
        )