Put the cursor in the new post where you want the image to appear. I usually leave a couple of blank lines above and below the image.
Then hit the "Upload a File" button (just below the window you are typing into) which will open a box where you can search for the image file on your computer. Select it and you should see it upload.
HotCopper recognizes that it's an image file and brings up a prompt which asks if you want a large image to appear or a thumbnail.
That's all. You should be able to see it when previewing your post. From memory, you can delete it and upload a new one if needed.
BTW, I found .jpg image files worked best. Didn't have any luck with .png etc.
