pretty as a picture意为“非常漂亮的，美如画的”。

【例句】
The countryside is as pretty as a picture.
乡村风景美如画。

Youth is as pretty as a picture, with the most beauteous memory in our life engraved on it.
青春是一幅优美的画卷，里面镌刻着一生中最美好的记忆。