Teacher takes pictures of students during exams and posts them on social media There's this teacher who takes pictures of his students during exams, and posts them on social media, with the knowledge of the students. A lot of people enjoy these pictures (including the students), but I'm not sure how I should feel about this.

This also includes editing pictures to make them into memes of some kind. There is no foul play involved, just for fun.

Is this behavior alright? Should it be tolerated? 

Addition :

The students were not asked for their consent. There have been no verbal objections, so far.
Doing this without permission is unprofessional, and it may be illegal, depending on your jurisdiction.

Asking for students' permission first is still unprofessional, especially in an exam situation, where students are already nervous, and given the power imbalance between the professor and the students. Who among the students will dare to object right before the exam? (This could depend on your local culture.)

You write that "There is no foul play involved, just for fun." - What is fun for one student could very well be harrassment for another, especially if pictures are edited. I don't see how this furthers the academic enterprise, so I would avoid doing this, at the risk of coming across as a spoilsport.

I surmise this question could soon be closed as opinion-based.