How to use getUserPicture?

when calling : [facebookClient getUserPicture] ;  
it return :

Social Client[20148:207] -JSONValue failed. Error trace is: (
    "Error Domain=org.brautaset.JSON.ErrorDomain Code=3 \"Unrecognised leading character\" UserInfo=0x8a7c9e0 {NSLocalizedDescription=Unrecognised leading character}"

I think it try to parse image binary as json in facebookGotResponse.

and also how to get all user photos?
