Does the option to add an image via URL not work? I have tried in both Brave and Firefox desktop browsers and the Brave mobile app - clicking the "From URL" or "Upload File" doesn't appear to do anything.
The only thing that does anything from this menu is clicking the filepath to upload a file from local.
You can paste an image URL in the file upload and it will save the image to kbin and post that. Not the same thing you're looking for but it's a workaround.