Welcome to the forum!
You selected the thumbnail image from the album; [ img]http://photos.cubfest.com/albums/userpics/13489/thumb_
To show the image larger in the post you need to open the photo from the album, right click on photo, select properties, copy the URL, and paste between the 'image' tags. I put a space just before the 'i' in the first tag so you can see what it will look like in your post before submitting. Without the space in front of the 'i', the image itself will show.
[ img]http://photos.cubfest.com/albums/userpics/13489/Lil_Red.JPG[/img] (notice the space in front of the 'i' in the first image tag)
Enjoy the tractor and the forum.