image_proxy.py

#!/usr/bin/env python3
from flask import Flask, Response, abort, request
from PIL import Image
import requests

try:
  from StringIO import BytesIO
except ImportError:
  from io import BytesIO

MAX_IMAGE_SIZE = 5 * 1024 * 1024

app = Flask(__name__) 
app.config.from_object(__name__)

@app.route('/')
def index():
  return Response("Use /convert?url=<image url>")

@app.route('/convert')
def convert_image():
  url = request.args.get('url', None)
  if url is None:
    abort(401)

  try:
    remote_image = requests.get(url)
    if not remote_image.ok:    
      abort(401)
  except requests.RequestException:
    abort(401)

  image_f = BytesIO(remote_image.content)
  image_f.seek(0)

  original = Image.open(image_f)

  if image_f.getbuffer().nbytes >= MAX_IMAGE_SIZE:
    # Cut that sucker in half
    half = lambda x: int(x / 2)
    original = original.resize(map(half, original.size), Image.ANTIALIAS)

  converted = BytesIO()
  original.save(converted, "JPEG", optimize=True, quality=90)
  converted.seek(0)

  print(converted.getbuffer().nbytes / (1024 * 1024))

  return Response(converted, mimetype="image/jpeg")

if __name__ == '__main__':
  app.run(host='0.0.0.0')