To post pictures...
Go to
https://imgur.com.
Upload the files.
Move the mouse *down* onto the picture and a little menu appears with "Copy" and a down-arrow.
Click the down-arrow and select "Get share links".
Click the "copy" button for "BBCode (forums)".
Go to the Frontier forums and click the Insert Image icon then press <CNTL><V> in the "URL" edit line then click OK.
*You* will see something like this "([IMG)(img)https://i.imgur.com/46vGb8P.jpg(/img)(/IMG)" but with [] instead of (). However, if you click "Go Advanced" you'll see the posting *with* the image - like the one below:-
https://i.imgur.com/46vGb8P.jpg
Hope this helps.