I'm not a techie, but here's the Plain English view / explanation:
In order to post photographs within a message on this Discussion Forum, two things must happen:
- Your Photos Must be on the Internet.
First, the photographs must be hosted on a server, somewhere on the internet. In other words, the photographs must be on your webspace or on another website. That way, anyone with a computer and a browser (and access rights) can see them.
If you are using a photo sharing / hosting service, you will need to be certain that
you will be able to link to your photos from other sites. Some sites will let you see the photos that you upload to the site, and maybe your friends can also sign in and see them, but they won't let the photos be displayed through links on other sites (like this Discussion Forum). They probably impose this limit because they want people to sign in to the site and they want to limit traffic on their servers, among other reasons.
- You Put Links to Your Photos in Your Message.
Assuming that your photos are safely posted on the Internet (Step (1) above), you
will need to add links to the photos within the body of the message that you are posting here. The "Optional Image URL" box is an easy way to add the link to one of your photos. When people read your message (the description of the item), they will also see your photo (because of the link)
In order to post multiple photos within a message, you will need to use HTML, which is a bit more complicated, and beyond out scope, at least for now.
I believe that the problem that you must be experiencing is that you are using links to a sharing / hosting site that does not allow linking to the photos from other sites (like this one).
I hope this helps. I am certain that this is not technically accurate, but it should give you a sense of why this is happening.
Jeff