Currently, the only way to accomplish this is to make two of them side by side as a single object as you mentioned. Similar to stacking objects, I also have plans to allow multiple objects per tile and the ability to tweak the positioning to some extent. I am not happy with the current functionality myself, so I definitely have some improvements to make around placing objects. :)
I would recommend trying out Imgur for posting images, it seems to work really well. In previous posts, I was able to grab the "direct link" once I uploaded to Imgur then paste it in the post and press enter to embed it. Hopefully that helps!