Not easy to explain in non-tech terms but in essence, all you need to display a picture is the address of where it is hosted placed between the IMG tags, e.g.
[IMG]http://www.flickr.com/my-picture.jpg[/IMG]
For hosting, you might like to try out the TM-Image library. Instructions here:
https://www.tm-img.com/page/ifuAlso worth watching Bonesie's helpful video here:
https://youtu.be/-cY5NpXXyMwAnd unless you have a paid account with them forget Photobucket. They stopped allowing free third-party hosting some time ago and anything you might have had previously will be watermarked.