Picasa web albums - impossible to list all photos

Question

I've uploaded about 40k photos using the Google Photos uploader tool, and now I'm trying to get a list of those photos using the Picasa Web Albums Data API (as there is no separate Google Photos API that I'm aware of).

So far, it appears impossible to get a complete list of all of the photos because you can list only 1000 photos at a time and then use the start-index parameter to do paging, but the server returns an error once you use a start-index above 11000. With a start-index of 11000 this occurs:

gdata.photos.service.GooglePhotosException: (500, 'Internal Server Error', 'Deprecated offset is too large for a stream ID query. Please switch to using resume tokens.')

(I'm using Python, but have confirmed that the error is independent of the language library)

I'd be happy to switch to using "resume tokens" like the error indicates... except that they are not mentioned in any documentation that I could find.

This is an authenticated request and the URL I'm using looks like this:

https://picasaweb.google.com/data/feed/api/user/[myUserID]/albumid/[myAlbumID]?kind=photo&max-results=1000&start-index=11000

Can anyone show me an example request using resume tokens or point me to documentation on them? Or, if anyone knows of some other way to get a complete list of all of the photos in a large album, that'd be great too. Thanks!

EDIT: the problem happens in any language, but in Python you can reproduce it consistently with:

startIndex = 1
while 1:
    print '(fetching more photos)'
    photos = client.GetFeed(ALBUM_URL, limit=1000, start_index=startIndex)
    for photo in photos.entry:
        print 'startIndex:', startIndex
        startIndex += 1

where ALBUM_URL is like the URL I listed above and client is an authenticated instance of gdata.photos.service.PhotosService.