wants the world to know just how incredibly generous he is, posting a photo of himself handing cash to a homeless woman on an L.A. street ... through the window of his Ferrari.
Bieber -- who's worth a reported $130 million -- posted the photo on his Instagram
, along with the caption, "Always give back."
So here's a riddle for you: if Justin Bieber performs a good deed and doesn't Instagram a photo of it, does it really count?
We'll let you think about it.