Letting an app crop your photo automatically usually cuts off the wrong thing. Cropping it yourself takes ten seconds and keeps what matters.
Cropping decides what is in the picture. Resizing decides how many pixels it has. Doing them in that order means you never stretch anything.
For a profile picture, leave a little space around a face rather than filling the frame. Most platforms display it inside a circle and will clip the edges.
Cropping never costs quality. You are keeping fewer of the original pixels, not rebuilding them.
Crop square here, then resize to whatever the platform asks for, commonly 400 by 400 or larger.
The same tool rotates and flips as well as crops.
No.