The pictures must be hosted online somewhere to be viewable on this website.
1) While making a reply, choose "go advanced". If you then scroll down you will see a button that says "manage attachments" that will allow you to attach pictures that are on your computer. They will be hosted on this site, and attached to your post.
2) The second option is to host the pictures online on your own. I use picasaweb.google.com , many people use www.flickr.com or www.photobucket.com . Once hosted on a dedicated hosting site, you then reply to a thread and click the "insert image" button that looks like a small picture of a mountain with a yellow sky. Then put the link in when prompted.
I'm not sure what level of explanation you need here. Maybe I'll do a more complete write up at lunch.
You come back to the forum and when replying to or starting a thread, click the button in the red circle
It will ask you for the url for the image...paste it in there - continue with the text and hit "submit reply" - and your image will appear in the post.
Some post have links to their pictures like you mention, yet some actually show the picture in the post. What is the difference? Are they getting the link to activate somehow when the post is brought up?
the easiest way to load the pics is to create a free account at www.photobucket.com and load the pics there. you don't have to worry about the size on that site, they can be as large as you have on your computer. then when you want to insert them into a post on az, click on the little icon that look like this:
and cut and past the direct link of the picture you want from photobucket into the dialog box and click ok. very important, then take your cursor at the end of the line that appears in your post (after the last ]) and hit return. you can preview it to make sure it works.