[kannued]

Musnake, you had the solution. If I had posted another reply, I would have seen that, of course, the posts alternate background colours. Thank you for pointing me in the right direction. Essentially, there was nothing wrong.

Related to this, the width of the text-alone box is wider than the image-only post. In sending more posts to the topic, the first one with the buffalo seems to have set the width for that alternate color. Then the white text only background is the width for all subsequent posts of that color. Isn’t the idea to have the same width for all the posts? Isn’t that how it is designed?