Copied these instructions from another website (SingleTrackWorld)
Posting an Image
The image must be hosted on the internet somewhere.
If it is on your computer you must first upload it to a photo hosting site. Try a search for image hosting to get you started.
Once you have chosen the image you want to show on the forum you need to find its URL (universal resource locator – its location on the internet).
Do this by right clicking on the image and choosing “copy image location” (or similar wording depending on your web browser). Note that this must be the location of the image itself, not the URL of the page it is on.
Then go to the forum and type :
is the URL you just retrieved.