Lindsay Lohan & Madonna -- Who's Younger ... Looking?

Lindsay Lohan and Madonna were accidental (we think) twinsies in NYC last night ... which is great for Madonna, and ... not-so-great for LiLo.

Madge threw a party for the release of her new short film -- and posed for a photo with Lindsay ... both of them in matching black outfits, matching red lipstick, and matching curly blondish hair.