==> 내가이있는 NSURLConnection 방법은 연결 실패받을 경우 우리가 다운로드 할 수있는 일이라고 생각
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
// Clear the activeDownload property to allow later attempts
self.activeDownload = nil;
// Release the connection now that it's finished
self.imageConnection = nil;
//i think we can call the connection method again from here
self.activeDownload = [NSMutableData data];
// alloc+init and start an NSURLConnection; release on completion/failure
NSURLConnection *conn = [[NSURLConnection alloc] initWithRequest:
[NSURLRequest requestWithURL:
[NSURL URLWithString:appRecord.imageURLString]] delegate:self];
self.imageConnection = conn;
[conn release];
}