Starting from the beginning just for completeness.
Log in and select New Post in the top left.
Drag and drop the photos you want to add to the post.
A preview of the post comes up, add a title (necessary) and descriptions (optional) then Post To Community
A prompt will appear for confirmation, either button will work.
I selected "No, I wanted to grab a link"
A new prompt with a link appears, either button will work. Navigate to your home page and find your most recent post.
Click little down arrow top right of image and select "Get share links"
Select copy for BBCode (Forums) and paste here.
My preferred Chrome method:
Right click on the image and "Open Image In New Tab"
Copy the address bar and put it between the image tags on here.