Example of BytesIO and PIL for modifying images without saving them

imageFunctions.py

domain = 'watermark' # just an example of how to use bytesio with PIL, works better if you know more about the images you're using instead of using random ones which can have random dimensions.

import aiohttp
from urllib.parse import unquote
from io import BytesIO
from PIL import Image, ImageDraw, ImageFont

async def returnRandomCat():
    async with aiohttp.ClientSession() as session:
        async with session.get("https://aws.random.cat/meow") as resp:
            data = await resp.json()
            url = unquote(data["file"])
        async with session.get(url) as resp:
            data = await resp.read()
    d = BytesIO(data)
    d.seek(0)
    img = Image.open(d)
    draw = ImageDraw.Draw(img)
    font = ImageFont.truetype("static/fonts/Roboto-Light.ttf", 20)
    draw.text(
        (img.width - font.getsize(domain)[0] - 200, img.height - 200),
        domain,
        fill=(255, 0, 255),
        font=font,
    )
    # Put a border around the image
    draw.rectangle((0, 0, img.width, img.height), outline=(255, 255, 255), width=5)
    d.seek(0)
    img.save(d, "PNG")
    d.seek(0)
    return d