It doesn't feel like I've met him or her unless I take the picture.
If I don't take the picture it doesn't feel like I've met him or her.
写真は永遠だけど、思い出は一時的だということですね.
なら、これも使われます:
a picture lasts forever
この例文の「do」のかわりに「will」を使えます。
Without a picture, it won't feel like I really met him.
It won't feel like I truly met her unless I get a picture.
アメリカ合衆国 
