Flipping screen like in photoshop?

Im trying to figure out of theres a way to flip the rendered image or the 3d view in general, to get a fresh look at the some project I’ve been staring at for hours. For those of you who don’t know this is quite common when creating art

while looking through the camera in the viewport (by pressing 0 on the numberpad), do [S, X, X, -1, ENTER] then you can do [SHIFT+R] to repeat the action.

note, this will flip the camera only, so nothing in the viewport will be changed.

i could not find any easy way to flip the rendered image without using the compositor. witch is tedious.

Edit: Remember, camera has to be selected!

Thank you that worked