gistfile1.txt

  NSString *path = @"/stuff.json";
  NSMutableURLRequest *request = [[AFAPPAPIClient instance] multipartFormRequestWithMethod:@"POST" path:path parameters:params constructingBodyWithBlock: ^(id <AFMultipartFormData>formData) {
    
    for (int i=0; i<[self.sImages count]; i++) {
      NSData *imageData = UIImageJPEGRepresentation([self.sImages objectAtIndex:i], 0.7);
      [formData appendPartWithFileData:imageData name:@"pics[]" fileName:@"avatar.jpg" mimeType:@"image/jpeg"];

    }
  }];

  AFHTTPRequestOperation *operation = [[[AFHTTPRequestOperation alloc] initWithRequest:request] autorelease];
  
  operation.completionBlock = ^ {
    if (completeSelector) {
 
      NSLog(@"error %@", operation.error); // HERE I CAN SEE THE ERROR.
   
      //callback
    }
  };
  
    
  NSOperationQueue *queue = [[[NSOperationQueue alloc] init] autorelease];
  [queue addOperation:operation];