I'm as guilty as the next guy of taking a picture of a fish out of water. I've never "beached" a fish, or left it lying in the dirt, that seems like a really stupid thing to do unless you're going to be eating it.
But I'll pick a bass up by the lip and hold it out for a photo op, then give it a gentle supported release. I'll set a walleye on my hand for a picture, I'll support a pike horizontally and take a picture.
I don't believe there's anything wrong with that, and you'd be hard pressed to sell me that it's detrimental to the fish to have it out of water for the picture.
That said, I take pictures of maybe 1 in 20 fish I catch.