I haven't tried authoring an article myself, but a quick look now seems to indicate that you can't upload images, only link to them. This means images must be hosted on third parties, meaning you have to upload it there and if not directly under your control, it's vulnerable to link rot. It seems like this would be inconvenient.
You can upload images to the LessWrong wiki, and then link them from comments or posts. It's a bit roundabout, but the feature is there. The question is then, should it be made easier?
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.