no u

import csv, urllib.request

algs = []
case_names = []

with open("algs.txt", "r") as f:
    csvfile = csv.reader(f)
    for row in csvfile:
        algs.append(row[0])
        case_names.append(row[1])

images = []

for alg in algs:
    images.append("http://localhost/visualcube/visualcube.php?stage=cmll&fmt=png&size=500&view=plan&case={}".format(alg))

for n in range(len(images)):
    urllib.request.urlretrieve(images[n], case_names[n]+".png")