Compress the size of the given file with the particular `scale` until `max_size` limit is achieved.

compress_image.py

from PIL import Image
from io import BytesIO

def compress_image(original_file, max_size, scale):
    """
    It should compress the size of the given file with the particular `scale`
    until `max_size` limit is achieved.
    """

    assert(0.0 < scale < 1.0)
    orig_image = Image.open(original_file)
    cur_size = orig_image.size

    while True:
        cur_size = (int(cur_size[0] * scale), int(cur_size[1] * scale))
        resized_file = orig_image.resize(cur_size, Image.ANTIALIAS)

        with BytesIO() as file_bytes:
            resized_file.save(file_bytes, optimize=True, quality=95, format='jpeg')
            if file_bytes.tell() <= max_size:
                file_bytes.seek(0, 0)
                with open(original_file, 'wb') as f_output:
                    f_output.write(file_bytes.read())
                break

Sample usage:

compress_image(
    original_file=file_name,
    max_size=MAX_ALLOWED_MEDIA_SIZE,
    scale=0.9
)