On this one, the link you have just goes to a page that has the image on the page.
your link: https://imgur.com/fTK9dE2
image address: https://i.imgur.com/fTK9dE2.jpeg
(I got the image address by right clicking within imgur and selecting 'copy image address'
If I put the image address between the [img] it embeds it in the post for viewing. In this case, the only difference between the page with the image and the image address is the addition of .jpeg That isn't always the case and I don't know the reason for that.