Q:

How to get twitter profile picture in ios? 

I wrote the following code:
NSURL *url = [NSURL URLWithString:@"http://api.twitter.com/1.1/users/show.json"];

NSDictionary *params = [NSDictionary dictionaryWithObjectsAndKeys:username, @"screen_name" ,[[controller.engine accessToken] secret]];

TWRequest *request = [[TWRequest alloc] initWithURL:url parameters:params requestMethod:TWRequestMethodGET];

[request performRequestWithHandler:
 ^(NSData *responseData, NSHTTPURLResponse *urlResponse, NSError *error) {
     if (responseData) {
         NSDictionary *user = [NSJSONSerialization JSONObjectWithData:responseData
                                         options:NSJSONReadingAllowFragments
                                           error:NULL];

         NSString *profileImageUrl = [user objectForKey:@"profile_image_url"];

         NSLog(@"%@",profileImageUrl);
     }
 }];

But I always end up getting a Bad authentication error.  I feel I'm missing something.  Would anyone please check my code?  Or provide any suggestions to retrieve twitter user profile pictures? 
Thanks

A:

Have you considered using a 3rd party Twitter engine for this?  I've used FHSTwitterEngine with a fair amount of success, and it seems to be under active development. 
To pull a profile picture you would do something like this:
[[FHSTwitterEngine sharedEngine]permanentlySetConsumerKey:@"<consumer_key>" andSecret:@"<consumer_secret>"];
[[FHSTwitterEngine sharedEngine]showOAuthLoginControllerFromViewController:self
withCompletion:^(BOOL success) {
    if (success) {
        UIImage *profileImg = [[FHSTwitterEngine sharedEngine] getProfileImageForUsername:@"<username>" andSize:size];
    }
}];

