Posting images within The Forums can be a little confusing to begin with, as the boards do not host images like most social networks and some other forums do.
To post images here, they first must be hosted elsewhere on the net, in a location that is accessible via a URL. The best example of this would be something like a Dropbox Public Folder or deviantArt’s Sta.sh feature. They could also be hosted directly on a personal website or blog.
Once the image has been hosted, you will need the direct address of the image – this can be found by right-clicking on the image and selecting ‘copy image location’.
Paste this direct link into the dialogue box that pops up from the picture icon or 'IMG' icon as indicated below.
This will then generate the necessary html within the comment box to post the image (note the image will also automatically scale to fit the forum width).
This process applies to both creating discussions and commenting on discussions.