ImageLOader

ImageLoaderConfiguration configuration = ImageLoaderConfiguration.createDefault(context);
       ImageLoader  loader = ImageLoader.getInstance();
        loader.init(configuration);
        DisplayImageOptions displayImageOptions = new DisplayImageOptions.Builder()
                .cacheInMemory(true)
                .cacheOnDisk(true)

                .build();

二次采样

http://blog.csdn.net/qiaoshi96_bk/article/details/73205331