Looks like an arm and a hand to me. I'm sorry you had such an unhelpful tech. But I'm not shy about asking "What's that?" during my ultrasounds. I try to stay quiet so that the tech can concentrate on their work. Which is why your tech was so quiet. There's a disclaimer right on the screen in the room where I get my ultrasounds "I apologize if I am quiet, I am concentrating on your scan". They have a lot of things they need to measure/take pics of for your Dr to make sure everything is growing right and doesn't have any problems. I imagine that can be pretty difficult.
I've gotten really super quiet techs before, but I've also gotten techs that kind of narrate as they go along "Now I am trying to see the ....." "Now I'm going to take measurements of the ....."
I'm sorry you got a quiet tech, but that just means that your tech wasn't great at multi-tasking. Maybe try taking the unknown picture with to your next appt and see if your Dr can tell you what it is?