Welcome Paul!
Sounds like you have a pristine example of an early Alembic bass. Everyone here loves pictures so hopefully you will be able to upload them. This may help...
"First reduce the physical size; the maximum height is 1,200 pixels and the maximum width is also 1200 pixels. Next is reducing the file size; the maximum file size if 500kB, and no more than 10 attachments per post."
Once the photos are the right size it should be easy to use the attach feature when posting. If you start with the quick reply box, type in some text then hit preview and there will be options for attaching images. Unfortunately once you attach them and hit the "Preview" button again you won't see the pictures in the preview. Once you hit "Post" they will be visible. At least that is the way it works for me.