Amber Rose has an ass that just won't quit ... getting Photoshopped -- and here's a little before and ass-ter to prove it.

Amber posted a bunch of Instagram shots from her day at the beach in Hawaii -- and everything was so smooth. But then we got some paparazzi shots of her ass -- it's hard to miss -- and these pics are straight outta dimpleville.

Truth is Amber's in good company -- even Beyonce's been busted multiple times altering pics.

And say what you want about it, but that booty trapped Kanye West AND Wiz Khalifa.

Respect.

And from the no-filters-required department ... we offer these. On fleek.