old_contents: import hashlib
  import urllib
  from django import template
  register = template.Library()
  
  # return only the URL of the gravatar
  # TEMPLATE USE:  {{ email|gravatar_url:150 }}
  @register.filter
  def gravatar_url(email, size=128):
      # default image, doc: https://en.gravatar.com/site/implement/images/
      default = 'mm'
      return "https://www.gravatar.com/avatar/%s?%s" % (hashlib.md5(email.lower()).hexdigest(), urllib.urlencode({'d': default, 's': str(size)}))
  
new_contents: import hashlib
  import urllib
  from django import template
  from DCRM.settings import LANGUAGE_CODE
  register = template.Library()
  
  # return only the URL of the gravatar
  # TEMPLATE USE:  {{ email|gravatar_url:150 }}
  @register.filter
  def gravatar_url(email, size=128):
      # Optimize for Chinese
      url = "https://cdn.v2ex.com/gravatar/" if LANGUAGE_CODE == 'zh-hans' else "https://www.gravatar.com/avatar/"
      # default image, doc: https://en.gravatar.com/site/implement/images/
      default = 'mm'
      return url + "%s?%s" % (hashlib.md5(email.lower()).hexdigest(), urllib.urlencode({'d': default, 's': str(size)}))
  
subject: Optimize for Chinese