Put an exclamantion at the start of the link so it looks like this ![]() . The image URL goes in the parenteses and apparently alt text goes in the brackets (I've always just left mine blank because I didn't know until a couple days ago). So with your example it would be:
Which gives you this:
EDIT: apparently the host you're using gets removed automatically or something? Post looked good in preview then the domain got butchered.