If the previous article talked about bulk rotating, then this article talks about bulk flipping. You can do it both vertically and horizontally. This can be achieved by using the options -flip and -flop. This is also ery usable for you working in e.g. graphic design field.
Vertical (Up to Down)
for i in *.png; do convert -verbose -flip "$i" "`echo $i | sed 's/.png/-converted.png/g'`"; done;
Horizontal (Left to Right)
for i in *.png; do convert -verbose -flop "$i" "`echo $i | sed 's/.png/-converted.png/g'`"; done;
