Use SLRequest to post image in tweet - Image not shown

I'm trying to upload an image (from an iOS device) to a user's twitter account programmatically using SLRequest. The Tweet text is uploaded in the tweet, but the image never appears. The response status code is 200.

Obviously the basics work ok, otherwise the tweet would not be shown in the user's stream at all and I have checked that the image is found and that the (NSData) variable contains the expected number of bytes.

Check out the following code - As you can see form the commented out code, I have tried various different modifications without success... Any thoughts/help appreciated!

- (void) postToTwitter:(NSString *)postMessage withImageNamed:(NSString *)imageName {

    // Get Twitter account
    ACAccountStore *smAccount = [[ACAccountStore alloc] init];
    ACAccountType *smType = [smAccount accountTypeWithAccountTypeIdentifier:ACAccountTypeIdentifierTwitter];

    NSDictionary *postOptions = nil;

    // Attempt to post the postMessage
    [smAccount requestAccessToAccountsWithType:smType options:postOptions completion:^(BOOL accessGranted, NSError *error) {

        // Access code block

        if (accessGranted) {

            NSLog(@"Access permitted");

            NSArray *smAccountList = [smAccount accountsWithAccountType:smType];

            if ([smAccountList count] > 0) {

                // Get the first Twitter account
                ACAccount *postingAccount = [smAccountList lastObject];

                // Create the post request
                //SLRequest *postRequest = [SLRequest requestForServiceType:SLServiceTypeTwitter requestMethod:SLRequestMethodPOST URL:[NSURL URLWithString:@"https://api.twitter.com/1.1/statuses/update.json"] parameters:[NSDictionary dictionaryWithObject:postMessage forKey:@"status"]];
                //SLRequest *postRequest = [SLRequest requestForServiceType:SLServiceTypeTwitter requestMethod:SLRequestMethodPOST URL:[NSURL URLWithString:@"https://upload.twitter.com/1.1/media/upload.json"] parameters:nil];
                SLRequest *postRequest = [SLRequest requestForServiceType:SLServiceTypeTwitter requestMethod:SLRequestMethodPOST URL:[NSURL URLWithString:@"https://api.twitter.com/1.1/statuses/update.json"] parameters:nil];

                // Add image to post
                // TODO - Check which to use >
                UIImage *postImage = [UIImage imageNamed:imageName];
                //UIImage *postImage = [UIImage imageWithContentsOfFile:imageName];
                //NSData *imageData = UIImageJPEGRepresentation (postImage, 0.5f); // Set compression

                NSData *imageData = UIImagePNGRepresentation(postImage);

                //[postRequest addMultipartData:imageData withName:@"media" type:@"image/png" filename:@"image.png"];
                [postRequest addMultipartData:imageData withName:@"media[]" type:@"multipart/form-data" filename:@"image.png"];

                // Add text
                [postRequest addMultipartData:[postMessage dataUsingEncoding:NSUTF8StringEncoding] withName:@"status" type:@"multipart/form-data" filename:nil];

                // Execute the post
                [postRequest setAccount:postingAccount];
                [postRequest performRequestWithHandler:^(NSData *responseData, NSHTTPURLResponse *urlResponse, NSError *error) {

                    // Post code block
                    if (error) {

                        NSLog(@"Post failed - %@", error);

                        if (_delegate && [_delegate respondsToSelector:@selector(didNotPost:)])
                            [_delegate didNotPost:self];
                    } else {

                        NSLog(@"Post complete");

                        if (_delegate && [_delegate respondsToSelector:@selector(didPost:)])
                            [_delegate didPost:self];
                    }
                }];
            }
        } else {

            NSLog(@"Access denied - %@", error);

            if (_delegate && [_delegate respondsToSelector:@selector(didNotPost:)])
                [_delegate didNotPost:self];
        }


    } ];
}

And this is the response:

(lldb) po urlResponse
<NSHTTPURLResponse: 0x7fb9bf80> { URL: https://api.twitter.com/1.1/statuses/update.json } { status code: 200, headers {
    "Cache-Control" = "no-cache, no-store, must-revalidate, pre-check=0, post-check=0";
    "Content-Disposition" = "attachment; filename=json.json";
    "Content-Encoding" = gzip;
    "Content-Length" = 751;
    "Content-Type" = "application/json;charset=utf-8";
    Date = "Thu, 02 Apr 2015 17:14:20 GMT";
    Expires = "Tue, 31 Mar 1981 05:00:00 GMT";
    "Last-Modified" = "Thu, 02 Apr 2015 17:14:20 GMT";
    Pragma = "no-cache";
    Server = "tsa_b";
    "Set-Cookie" = "lang=en";
    Status = "200 OK";
    "Strict-Transport-Security" = "max-age=631138519";
    "x-access-level" = "read-write";
    "x-connection-hash" = 6f61f3c96ba990931cca3fa950a42b38;
    "x-content-type-options" = nosniff;
    "x-frame-options" = SAMEORIGIN;
    "x-response-time" = 51;
    "x-transaction" = b2c77803db7e996d;
    "x-tsa-request-body-time" = 426;
    "x-twitter-response-tags" = BouncerCompliant;
    "x-xss-protection" = "1; mode=block";
} }

So after much pain, I realised that I was posting to the wrong twitter API. The following modification made this work.

SLRequest *postRequest = [SLRequest requestForServiceType:SLServiceTypeTwitter requestMethod:SLRequestMethodPOST URL:[NSURL URLWithString:@"https://api.twitter.com/1.1/statuses/update_with_media.json"] parameters:nil];