There are two ways to include images in your new post:
Attaching images to your post is quite simple. First bring up the new post window:
At the bottom left you will see a button to attach an image. Click this button and locate your image. Using this method you can attach as many images as you'd like, albeit one at a time.
Attached images will be displayed at the bottom of your post.
Sometimes you want to use inline images that fall within your text. You can do so by typing an exclamation point followed by alt text in parenthesis and the path to the image in brackets, like this:
This method requires that the image you want to use is already available online and accessible using a URL.