Also, it's a good idea to include the direct link; just right-click the image and select "Copy image address" (that’s what it says in Chrome, anyway—not sure how other browsers handle it).
What part isn't clicking😁? First, type out (image) and make sure you close that bracket. If that's too much work, just look for that tiny yellow icon that looks like a little mountain when you're making a post. Click that, paste your link, and you're golden...