Discord.py重写不返回缓存图像

import discord
from discord.ext import commands
import os
import requests

# 设置缓存目录
CACHE_DIR = 'cache'
os.makedirs(CACHE_DIR, exist_ok=True)

bot = commands.Bot(command_prefix='!')

async def download_image(url, filename):
    response = requests.get(url)
    if response.status_code == 200:
        with open(filename, 'wb') as f:
            f.write(response.content)

@bot.command()
async def image(ctx, url: str):
    filename = os.path.join(CACHE_DIR, url.split('/')[-1])
    
    # 检查缓存是否存在
    if not os.path.exists(filename):
        await download_image(url, filename)
    
    # 发送缓存的图像
    await ctx.send(file=discord.File(filename))

bot.run('YOUR_BOT_TOKEN')