The former process for uploading images failed on its own. Fun days. Please try this process to upload a single image:
Begin the process of adding an image as you have before.
Click “Add image to post”
Click “Upload”
Now some choices should appear under “Embed codes”
Choose “BBCode Full image”
Now an option to “copy link” appears.
Copy that, back out of the image hosting process, and paste the copied code into your post
Post your post.

If you get stuck and can’t make it work I will try for you. PM me then send me pix via email.