UtilityMill is another powerfull python web based service which allow you to create python web services, by providing a lot of powered python librairies, including PIL !

The interesting thing is that it provides restull api. So it can be possible to do some things which are not available on gae, by using the gae fetch function. It's better than nothing.

This one provides a thumbnailer service. I hadn't done an implementation of this one. But here is a stupid implementation for using the rot13 web service of UtilityMill:

from google.appengine.api import urlfetch
from xml.etree import ElementTree
import urllib

def getRot13(txt):
    service="rot13"
    version=13
    url="http://utilitymill.com/api/xml/utility/%s/%d/run?textIn=%s" % (
                service, version, urllib.quote_plus(txt) )

    result = urlfetch.fetch(url)
    if result.status_code==200:
        dom=ElementTree.fromstring(result.content)
        return dom.find("output").text
    else:
        return None

print getRot13("Hello from rot13 !")