Hi @Bookman53 - hope you're keeping well!
This is actually a great question and we're glad it's come up, this will be useful for the entire community!
You have two options for uploading images - one is to use the 'upload' icon to upload an image file, in which case the image would be put at the bottom of the post. You can also use the 'copy & paste' method, just pasting into the text box and the image should upload.
We've seen the 'duplication' - but it seems to be a display issue for the user, where if you refresh the page it should not longer show double. Our tech team is looking into this further,
The second option is to select the 'add an image' in which case the code you mentioned shows in the text field.
In that case, I've got a handy image I can share below that clarifies how to use that to insert an image in the middle of your text.
Blue is the text on either side of the image, yellow is the name of the image, and green is the external link to the image.
This requires that the image be uploaded somewhere accessible of course.