Oh, I see!
Like a ':)' face.
But sideways!
Okay, I see it now. It is very cute!

...I see the proper button now, as well.
So it is an entirely different function from the camera that is used when making a post!
I kept trying to figure out how to take a picture without posting it to the network but now I see I have been going about it all wrong.
Thank you very much, Alphys!
I am certain it would have been quite strange to suddenly flood the network with pictures of my girlfriend.