Yep, this is a very good rule of thumb when viewing pictures these days.
Only because with the advent of powerful editing software, no picture remains untouched. And I mean not one single picture in advertisements, posters, TV commercials (yes even moving pictures), packagings, editorials, magazines, and of course portfolios of lovely FLs.
It is not a common practice, it is a NORMAL practice! Guys, this is the way of the world now. Photographers don't even need to be competent anymore!!!
Referred to as photoshop, retouching or digital imaging (DI), the powerful software is also damn easy to use. Sometimes, with pre-set command functions, all it take is a click and miracles happen!
OK, the most basic mandatory things a retoucher does with a picture. Don't even need to instruct - 1) Create an even skin tone by adding a gossier blur, obvious dark patches are "stamped" away. 2) Remove or reducing facial lines and creases, especially around the eyes, mouth and neck. 3) Brightening eyes by making the whites whiter 4) Removing dark eye circles and bags.
These are only the basics, but already the person in the picture will look younger, fresher and more appealing.
Another thing that can also be simply done to achieve a more beautiful picture is "skewing". Eyes can be made larger. By slightly lenghtening the torso, a more elegant body can be achieved. Also elongating the face, cutting away the bulgy bits here and there... voila!!!
Take a look at this video...
Once again, this is the way of the world now. Even your neighbourhood HDB photo studio does it