Upload multiple images in one request

I want to upload more than one image in single service request. How can I do that. As of now I am able to upload single image like as

 NSData *imageData = UIImageJPEGRepresentation(image, 90);


 NSString *boundary = @"---------------------------14737809831466499882746641449";


   NSString *contentType = [NSString stringWithFormat:@"multipart/form-data; boundary=%@",boundary];

NSMutableData *postBody = [NSMutableData data];

// file
[postBody appendData:[[NSString stringWithFormat:@"\r\n--%@\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]];
[postBody appendData:[[NSString stringWithString:[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"files\"; filename=\”%@\”\r\n”,@“imagename”]] dataUsingEncoding:NSUTF8StringEncoding]];
[postBody appendData:[@"Content-Type: application/octet-stream\r\n\r\n" dataUsingEncoding:NSUTF8StringEncoding]];
[postBody appendData:[NSData dataWithData:imageData]];
[postBody appendData:[[NSString stringWithFormat:@"\r\n--%@--\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]];


[postBody appendData:[@"\r\n" dataUsingEncoding:NSUTF8StringEncoding]];

Now I want to upload two images to server how can I do that.