Flip a picture horizontally or vertically, or fold one half onto the other for a symmetrical mirror composition. The pixels stay exactly as they were; only the geometry changes.
How the mirror & flip image tool works
Upload your image. Say which transform you want: 'flip horizontally', 'flip vertically', or 'mirror the left half onto the right for a symmetrical image'. For a mirror composite, name the axis and which side to keep. Run the tool and check any text in the shot, since flipping reverses it. If you wanted a seamless symmetry, look along the centre seam and rerun with a note about blending it if needed.
Tips for the best results
Flipping reverses any lettering, so ask for text to be left readable if the shot contains signage. For symmetry effects, say which half is the keeper, since the more interesting half usually makes the better mirror. Vertical flips read as reflections and often look best with a water or glass surface in frame.