Example how to use the API v3 of "The Movie Database" (themoviedb.org). Saves all available posters for the movie with IMDb id tt0095016 to the current folder, using the maximum available resolution.

tutorial_themoviedb.py

import os
import requests

CONFIG_PATTERN = 'http://api.themoviedb.org/3/configuration?api_key={key}'
IMG_PATTERN = 'http://api.themoviedb.org/3/movie/{imdbid}/images?api_key={key}' 
KEY = '<your_api_key>'
            
def _get_json(url):
    r = requests.get(url)
    return r.json()
    
def _download_images(urls, path='.'):
    """download all images in list 'urls' to 'path' """

    for nr, url in enumerate(urls):
        r = requests.get(url)
        filetype = r.headers['content-type'].split('/')[-1]
        filename = 'poster_{0}.{1}'.format(nr+1,filetype)
        filepath = os.path.join(path, filename)
        with open(filepath,'wb') as w:
            w.write(r.content)

def get_poster_urls(imdbid):
    """ return image urls of posters for IMDB id

        returns all poster images from 'themoviedb.org'. Uses the
        maximum available size. 

        Args:
            imdbid (str): IMDB id of the movie

        Returns:
            list: list of urls to the images
    """
    config = _get_json(CONFIG_PATTERN.format(key=KEY))
    base_url = config['images']['base_url']
    sizes = config['images']['poster_sizes']

    """
        'sizes' should be sorted in ascending order, so
            max_size = sizes[-1]
        should get the largest size as well.        
    """
    def size_str_to_int(x):
        return float("inf") if x == 'original' else int(x[1:])
    max_size = max(sizes, key=size_str_to_int)

    posters = _get_json(IMG_PATTERN.format(key=KEY,imdbid=imdbid))['posters']
    poster_urls = []
    for poster in posters:
        rel_path = poster['file_path']
        url = "{0}{1}{2}".format(base_url, max_size, rel_path)
        poster_urls.append(url) 

    return poster_urls

def tmdb_posters(imdbid, count=None, outpath='.'):    
    urls = get_poster_urls(imdbid)
    if count is not None:
        urls = urls[:count]
    _download_images(urls, outpath)

if __name__=="__main__":
    tmdb_posters('tt0095016')