Legality of using other users Facebook images

MY QUESTION:   How would you feel  if I just took images from a facebook group page, images that you posted, and used them to make content for my own youtube channel?

Recently in a facebook group which is about photoshop elements I noticed some activity from one user I found a bit odd.

Typically, within 4 days of a user posting an image and asking "I need help with this shadow" or "How do I match the colors in these photos?"  The same exact image appears as a "tutorial" on his Youtube channel.

Many of the images used are of children:  football team picture, cheerleader picture, kid in a family picture type stuff.

I checked with 5 users: Only one had given permission.   One user contacted him and had the video removed.

All the videos on his youtube channel have commenting disabled, which leaves a sour taste in my mouth.

It all seems to be just a bad way of doing business to me.