twitter_upload_media.m

    NSString *boundary = @"cce6735153bf14e47e999e68bb183e70a1fa7fc89722fc1efdf03a917340";
    
    // create request
    NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init];
    [request setCachePolicy:NSURLRequestReloadIgnoringLocalCacheData];
    [request setHTTPShouldHandleCookies:NO];
    [request setTimeoutInterval:30];
    [request setHTTPMethod:@"POST"];
    
    // set Content-Type in HTTP header
    NSString *contentType = [NSString stringWithFormat:@"multipart/form-data; boundary=%@", boundary];
    [request setValue:contentType forHTTPHeaderField: @"Content-Type"];
    
    // post body
    NSMutableData *body = [NSMutableData data];
    
    // add status param
    [body appendData:[[NSString stringWithFormat:@"--%@\r\n", boundary] dataUsingEncoding:NSUTF8StringEncoding]];
    [body appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"status\"\r\n\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
    [body appendData:[[NSString stringWithFormat:@"%@\r\n", @"The status with image"] dataUsingEncoding:NSUTF8StringEncoding]];
    
    // add image data
    NSData *imageData = UIImageJPEGRepresentation([UIImage imageNamed:@"tori.jpg"], 1.0);
    if (imageData) {
        [body appendData:[[NSString stringWithFormat:@"--%@\r\n", boundary] dataUsingEncoding:NSUTF8StringEncoding]];
        [body appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"media[]\"; filename=\"media.png\"\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
        [body appendData:[[NSString stringWithFormat:@"Content-Type: application/octet-stream\r\n\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
        [body appendData:imageData];
        [body appendData:[[NSString stringWithFormat:@"\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
    }
    
    [body appendData:[[NSString stringWithFormat:@"--%@--\r\n", boundary] dataUsingEncoding:NSUTF8StringEncoding]];
    
    // setting the body of the post to the reqeust
    [request setHTTPBody:body];
    
    // set URL
    [request setURL:[NSURL URLWithString:@"https://api.twitter.com/1.1/statuses/update_with_media.json"]];
    
    [[PFTwitterUtils twitter] signRequest:request];
    
    AFJSONRequestOperation *operation = [AFJSONRequestOperation JSONRequestOperationWithRequest:request
                                                                                        success:^(NSURLRequest *request, NSHTTPURLResponse *response, id JSON) {
                                                                                            NSLog(@"Oh Yes: %@",[JSON valueForKey:@"created_at"]);
                                                                                        } failure:^(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error, id JSON) {
                                                                                            NSLog(@"Oh No");
                                                                                        }];
    [operation start];