see attached image, but basically having the images on the right side makes it so hard to “read” a post with an image, going back and forth with your eyes to “get” the whole post. So much easier to just put the images between the up-/downvote buttons and the text post.
I don’t know if there’s a reason for that besides looking different from similar sites. If so, I don’t think this is the way, it really puts a strain on your eyes and our brain is not used to absorb information in this way.
I hadn’t realised this was an issue, but now you’ve pointed it out, images would definitely be nicer on the left. It’s just a better read!