import numpy as np
places = np.array([x for x in range(312, 333)])
tomes = ['I','II','III']
pages = ['01', '02', '03', '04', '05', '06', '07', '08', '09', '10', '11', '12', '13', '14', '15', '16', '17', '18', '19']

import requests
for pl in places:
    for t in tomes:
        for pa in pages:
            img = 'http://alpi.csic.es/cuadernillos/{}/{}/{}-{}_Pagina_{}.jpg'.format(pl, t, pl, t, pa)
            img_name = '{}_{}_{}.jpg'.format(pl, t, pa)
            p = requests.get(img)
            if p.status_code != 404:
                out = open('{}'.format(img_name), "wb+")
                out.write(p.content)
                out.close()