Someone recently give me a link to a web picasa photo album. I wanted to download all the photo in good resolution, but the only official way to download it is by using the picasa proprietary software.

Not only I'm not thrilled to install yet another unfree software, but Google refuse me to download it because "Picasa is not currently available for your operating system". Another solution exist, but need some research:

Some time, its great to be able to beat limitation of unfree software thanks to free software.

It's old, but it's free and it still works: Pycasa. It's what I use to occasionally download Picasa albums.
Comment by Martijn Mon Jul 16 10:43:44 2012

I wrote a script once to download all images, dunno if it still works...

# -*- coding: utf-8 -*-
import sys
import urllib2
from os.path import join
from lxml import etree

argv_len = len(sys.argv)
if argv_len not in (2, 3):
    print 'link to albums\' RSS feed is missing'
if argv_len == 3:
    dstdir = sys.argv[-1]
    dstdir = '.'

album_url = sys.argv[1]
if album_url.startswith('/'):
    album_url = "file://%s" % album_url

rss_data = urllib2.urlopen(album_url).read()
exml = etree.fromstring(rss_data)

urls = exml.xpath('.//item/media:group/media:content/@url', namespaces={'media': ''})
for url in urls:
    fn = url.rsplit('/', 1)[-1]
    fp = open(join(dstdir, fn), 'w')
Comment by Piotr Mon Jul 16 11:10:00 2012
I did it with digikam. Everything was ok, but I couldn't download all the albums at once, as I wanted.
Comment by Robert Mon Jul 16 12:02:03 2012
It's not actually fully true, View image from context menu gives a link with a component looking like s800 which you can replace with s1600 if you want. Or you can save it just as it is if it's of already acceptable quality.
Comment by Andrew Mon Jul 16 14:39:33 2012
Ah, sorry, misread your post re 'all the photos'. Feel free to discard both comments. However, there's RSS feed which links to all the photos and which is actually used by desktop Picasa...
Comment by Andrew Mon Jul 16 14:41:42 2012
Using the rss stream might be a simple solution too. I didn't test it.
Comment by remi Mon Jul 16 20:40:35 2012