To override the Content-type in your clients HTTP Accept Header, append  the .json suffix or  ?format=json
To embed the response in a jsonp callback, append ?callback=myCallback
        
        HTTP + JSON
         The following are sample HTTP requests and responses. 
            The placeholders shown need to be replaced with actual values.
POST /json/reply/AttachmentGet HTTP/1.1 
Host: partnerhub.pbsdealers.com 
Content-Type: application/json
Content-Length: length
{"SerialNumber":"String","AttachmentId":"00000000000000000000000000000000","ScaleWidth":0,"ScaleHeight":0}
 
HTTP/1.1 200 OK
Content-Type: application/json
Content-Length: length
{"AttachmentId":"00000000000000000000000000000000","FileName":"String","Description":"String","Data":"AA==","FileType":0,"Visibility":0}