UIWebView loading slow if using baseUrl

Question

this works very well and fast but it does not load images if I give baseurl instead of nil. It takes few seconds to load.

NSURL *myUrl = [[NSURL alloc] initFileURLWithPath:self.contentPath];
//NSLog(@”Content url is %@”,myUrl);

NSString *string = [[NSString alloc]initWithContentsOfFile:self.contentPath encoding:NSASCIIStringEncoding error:nil];
[contentDisplay loadHTMLString:string baseURL:nil]; //here nil if replaced by myUrl webView takes time to load. Any help ?
[string release];
[myUrl release];