PIL.Image is a module, you can not call it by Image(...), maybe you need call it by Image.open(...). At the same, tkinter/PySimpleGUI cannot handle JPG image, so conversion to PNG image is required.

from io import BytesIO
import PySimpleGUI as sg
from PIL import Image
import requests, json

def image_to_data(im):
    """
    Image object to bytes object.
    : Parameters
      im - Image object
    : Return
      bytes object.
    """
    with BytesIO() as output:
        im.save(output, format="PNG")
        data = output.getvalue()
    return data

cutURL = 'https://meme-api-python.herokuapp.com/gimme'

imageURL = json.loads(requests.get(cutURL).content)["url"]
data = requests.get(imageURL).content
stream = BytesIO(data)
img = Image.open(stream)

img_box = sg.Image(image_to_data(img))

window = sg.Window('', [[img_box]], finalize=True)

# Check if the size of the window is greater than the screen
w1, h1 = window.size
w2, h2 = sg.Window.get_screen_size()
if w1>w2 or h1>h2:
    window.move(0, 0)

while True:
    event, values = window.read()
    if event is None:
        break
window.close()

[multipart data POST using python requests: no multipart boundary was found

Above link was helpful. I removed explicit header and Parameters, and it worked.

import requests

files = {
    'form': ('images.jpg',open('images.jpg', 'rb'),'image/jpg'),
}

response = requests.post('http://localhost:5000/face/v1.0/detect?returnFaceId=true&returnFaceLandmarks=false', files=files)
print(response.json())

You are just printing the image URL. You need to write the image contents to a file, that's how you can download them. There are also other methods like using wget library too. But here is how you can do it as well:

import requests

url = "https://www.habbo.es/extradata/public/users/hhes-aafb213bbe8a70df33faa0259cfb5f33/photos"
data = requests.get(url).json()
for key in data:
    image_url = 'https:' + key['url']
    response = requests.get(image_url)
    filename = data[0]['url'].split("/")[-1]
    if response.status_code == 200:
        with open(filename, 'wb') as f:
            f.write(response.content)