iOS GIF图片导入到相册处理方法
通过路径转成data数据，写入本地相册就行了：
NSData *data = [NSData dataWithContentsOfFile:path];
// 保存到本地相册
ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
[library writeImageDataToSavedPhotosAlbum:data metadata:nil completionBlock:^(NSURL *assetURL, NSError *error) {
NSLog(@"Success at %@", [assetURL path] );
}] ; N
