Gee, really?
Did that. Source window comes up. Two choices, paste or look up. I’m trying to post an image from my photos. No option for that. But thanks.
Ok that makes sense. Uploading images to the site currently isn’t an allowed. Upload your image to somewhere and copy the image URL, then paste image URL in the image dialog.
Most boards don’t allow that. Just go to something like imgbb etc. and then get the image direct link (the file path only, not the page on which the image is framed). It used to be easier on an imgur but then imgur decided it was a social media company and made direct linking harder.
It’s like one minute longer if you practice. You can do it.