While making your post, put the edit cursor where you want the image to appear. At the bottom, you'll see upload image (fourth button over). That will make a pop-up that will allow you to upload your image. Be sure to follow the image policy; it's linked on the right side of the pop-up. Once the upload is complete, the new window will have a line that says to add it to your post. Click that, and it will add the necessary code to make your image display.

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