title: iOS6 UIImage causes crash
body: <p>Since iOS6 I have a very weird issue with UIImages that causes the application to crash.
  The full method is like this:</p>
  
  <pre><code>NSURL *url = [NSURL URLWithString:@"http://api.twitter.com/1/users/show.json"];
  
  NSDictionary *parametros = [NSDictionary dictionaryWithObjectsAndKeys:account.username, @"screen_name", nil];
  
  SLRequest *request = [SLRequest requestForServiceType:SLServiceTypeTwitter
                              requestMethod:SLRequestMethodGET
                              URL:url
                              parameters:parametros];
  [request setAccount:account];
  [request performRequestWithHandler:^(NSData *responseData, NSHTTPURLResponse *urlResponse, NSError *error) {
          if ([urlResponse statusCode] == 200) {
              NSError *error_ = nil;
              NSDictionary *userInfo = [NSJSONSerialization JSONObjectWithData:responseData options:kNilOptions error:&amp;error_];
              UIImage *image = [UIImage imageWithData:[userInfo objectForKey:@"profile_image_url"]];
              UIImage *image = [UIImage imageWithData:[userInfo objectForKey:@"profile_image_url"]];
              dispatch_sync(dispatch_get_main_queue(), ^{
                  [_imageCache setObject:image forKey:account.username];
                  [ListAccount reloadRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:NO];
              });
          }
      }];
  </code></pre>
  
  <p>The problem occur in this line</p>
  
  <pre><code>UIImage *image = [UIImage imageWithData:[userInfo objectForKey:@"profile_image_url"]];
  </code></pre>
  
  <p>This was no problem in iOS5. I can't seem to find why or someone that had the same problem. Any suggestion will be really appreciated </p>
  
  <p>The crash is the following: </p>
  
  <pre><code>2012-09-28 17:30:53.600 Catalogo[7321:c07] -[__NSCFString bytes]: unrecognized selector     sent to instance 0x10eaf180
  2012-09-28 17:30:53.601 Catalogo[7321:c07] *** Terminating app due to uncaught exception     'NSInvalidArgumentException', reason: '-[__NSCFString bytes]: unrecognized selector sent to     instance 0x10eaf180'
  *** First throw call stack:
  (0x2aed012 0x1a28e7e 0x2b784bd 0x2adcbbc 0x2adc94e 0x2a75390 0x203630c 0x2035e7e 0x2035d98     0x10dc23d 0xf991f3 0xf98ef4 0x6c54e 0x1b9e731 0x1bad014 0x1b9d7d5 0x2a93af5 0x2a92f44     0x2a92e1b 0x2dd87e3 0x2dd8668 0xf7765c 0x79cd 0x2d45)
  libc++abi.dylib: terminate called throwing an exception
  </code></pre>
  
  <p>The following:</p>
  
  <pre><code>[userInfo objectForKey:@"profile_image_url"]
  </code></pre>
  
  <p>return the url of a twitter profile image </p>