Ok firstly please use a image hosting site to host pictures do not attach photos to messages as this takes the data storage from the site.
Here is how to post a picture from photobucket like I have here (couldnt resist a cute pic) instead of a link also the same principle will apply from other image hosting sites such as image shack etc
Once you have uploaded the picture to photobucket click it up so it is larger and there will be a series of links to the side of the photo click the one that the arrow in the following photo points to which is the img code and it will highlight yellow to show it has been copied.
once you have done that go to a post either as a new thread or a reply and right click your mouse button and click on paste and the link will show up on the post. It will stay as a link and not show as a picture until you press reply or submit new post.
Have a practice in this thread if you want and I will help as much as I can if you get stuck.