OK, a bit more testing with the imgur site, and this DOES work with the "Insert Image" button here:
1. Upload an image to imgur.com (I used the W10 screen snip tool).
2. Hoover the mouse over the image now on imgur.com and click on the "Copy link" button.
3. Back on this forum, click on the "Insert Image" button and past the link, but at the end of the pasted information ADD the file extension(".png" for me). No other change is needed.
4. Now when you click OK, the correct link will be inserted in your post to embed the image.