async def crawler(loop):
    urls = ...

    async with aiohttp.ClientSession(loop=loop) as session:
        for url in urls:
            try:
                async with session.get(url) as response:
                    image = await response.read()
                    image = Image.open(io.BytesIO(image))
                    image.save(...)
            except Exception:
                pass


loop = asyncio.get_event_loop()
loop.run_until_complete(crawler(loop))