I heard this yesterday from a neighbour as we chatted briefly - no kids around at the time.
Basically, according to her it seems a thing that teenagers have printed out pictures of their teachers on mugs, and just have them and think its funny. Her DD has one, for example, and finds it hilarious. She did not say whether she had removed it, or talked about it, just that it was a laugh.
Also that, generally, teenagers find it very easy and hilarious to find photos and/or tik toks of their teachers online and do something with them.
That last part I have no problems believing or having versions of like screen shots and manipulations etc - but teacher faces on mugs? Is that really a thing?