Ojbective C将多张图片复制到图片库

注意保存图片引用的images不能是autorelease的

- (void) saveImagesToPhotosAlbum:(NSMutableSet *)images {
    if (images.count == 0) {
        [images release];
         
        return;
    }
    UIImage *image = [[[images anyObject] retain] autorelease];
    [images removeObject:image];
    UIImageWriteToSavedPhotosAlbum(image,
                                   self,
                                   @selector(image:didFinishSavingWithError:contextInfo:),
                                   images);
}
 
- (void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo {
    [self saveImagesToPhotosAlbum:(NSMutableSet *)contextInfo];
}