根据url多线程请求载入网络图片

-(void) processDownloadImageData:(NSData *) imageData

{

    NSString *imagePath = [NSString stringWithFormat:@"%@/avatar%@.png",document,pathuserID];

    if (![imageData writeToFile:imagePath atomically:YES]) {

        NSLog(@"save imageData Error with path:%@",imagePath);

    }

   //do anything if you want 

}//接收到图片后的处理函数

-(void) loadImagebyThread:(NSString *) imageUrlStr

{

    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];

    NSURL *imgUrl = [NSURL URLWithString:imageUrlStr];

    NSData *imgData = [NSData dataWithContentsOfURL:imgUrl];    

    if (imgData) {

        [self performSelectorOnMainThread:@selector(processDownloadImageData:) withObject:imgData waitUntilDone:NO];

    }

    [pool release];

}//请求图片的线程函数

在某个需要的地方添加多线程：

                NSString *avatar_large_urlStr = [profileDic objectForKey:@"avatar_large"];

                [NSThread detachNewThreadSelector:@selector(loadImagebyThread:) toTarget:self withObject:avatar_large_urlStr];