+ * First lookup in the contact table to find a record matching either `url`, `nurl`,
+ * `addr` or `alias`.
+ *
+ * If there's no record and we aren't looking for a public contact, we quit.
+ * If there's one, we check that it isn't time to update the picture else we
+ * directly return the found contact id.
+ *
+ * Second, we probe the provided $url wether it's http://server.tld/profile or
+ * nick@server.tld. We quit if we can't get any info back.
+ *
+ * Third, we create the contact record if it doesn't exist
+ *
+ * Fourth, we update the existing record with the new data (avatar, alias, nick)
+ * if there's any updates
+ *