Upside down = 裏返し、逆さまの時でも使えます。
Turned over = 裏返した、裏返してる
I took a picture of my fortune cookie paper, but when I got home I realized the paper was turned over.(upside down)
back to front / the wrong way round / face down / be turned over
I took a photo of the fortune cookie paper but when I got home and checked, I found the paper was face down (turned over)
「裏返し」＝ back to front / the wrong way round / face down / be turned over
※紙の話だから、「face down」か「be turned over」が一番合う言い方です。
「フォーチュンクッキーの紙を写真撮って家に帰って確認したら紙が裏返しだった」＝ I took a photo of the fortune cookie paper but when I got home and checked, I found the paper was face down (turned over)
アメリカ合衆国 
イギリス 
