问云通信的图片发送示例代码不能用，无法发送图片？

Request URL:https://pic.tim.qq.com/v4/openpic/pic_up?websdkappid=537048168&v=1.7.0&platform=10&tinyid=144115209568981667&a2=d783d643e6539057d5066cba092402745e590694625899850620156df5f9a6518620fd0772a057eea0f17499edf73de5302b2e99011d2dd590ba164252f44ce49ce20dd6342f54a6&contenttype=json&sdkappid=1400034962&apn=1&reqtime=1507865543

Request Method:POST

Status Code:200

postData:

{"App_Version":"2.1","From_Account":"1:2:kkkkkkkk:0","To_Account":"@TGS#1HCXGU5EX","accounttype":"GROUP","Seq":615030,"Timestamp":1507865367,"Random":101458959,"File_Str_Md5":"2fe3b450cc7c35d796f2da052c119813","File_Size":105524,"Server_Ver":1,"Auth_Key":"3043020101043c303a02010102010102040cec95fa02037a1db9020437fd03b7020437fd03b702037a1afd02041116a3b402041a16a3b4020459e81c1402045e048eaa0400","Busi_Id":1,"PkgFlag":1,"Slice_Offset":0,"Slice_Size":105524,"Slice_Data":"/9j/4AAQSkZJRgA.........

ps: accounttype是我自己加的

res: