Toma esta respuesta json:

    {
   "self":"http://macpro.local:2990/jira/rest/api/2/issue/CSS-4/votes",
   "votes":2,
   "hasVoted":true,
   "voters":[
      {
         "self":"http://macpro.local:2990/jira/rest/api/2/user?username=admin",
         "name":"admin",
         "avatarUrls":{
            "16x16":"http://macpro.local:2990/jira/secure/useravatar?size=small&avatarId=10062",
            "48x48":"http://macpro.local:2990/jira/secure/useravatar?avatarId=10062"
         },
         "displayName":"admin",
         "active":true
      },
      {
         "self":"http://macpro.local:2990/jira/rest/api/2/user?username=timn_1",
         "name":"timn_1",
         "avatarUrls":{
            "16x16":"http://macpro.local:2990/jira/secure/useravatar?size=small&avatarId=10062",
            "48x48":"http://macpro.local:2990/jira/secure/useravatar?avatarId=10062"
         },
         "displayName":"User Two",
         "active":true
      }
   ]
}

No sé cómo obtener los avatarUrls-> 16x16 desde arriba. He estado recibiendo todo lo demás con bastante facilidad con comandos como:

$decoded = json_decode($result);
$decoded->votes; //returns # of votes
$decoded->voters->name; //returns the name

Pero, ¿cómo obtengo el valor 16x16? Me sale un error si intento esto:

$decoded->voters->avatarUrls->16x16;