I disagree with this. If I'm in a poor connectivity situation, a preview can help me quickly decide if an image is worth waiting for.

I'm not talking about blurhash here - those are 'cute' at best. I'm talking about previews that let me determine the subject of an image.

I was on a train recently and an image preview X delivered to me was enough for me to tell that the image was a particular meme format, and thanks to context, I knew enough about the image, and didn't bother waiting for it to load.