Your image doesn't show here because the HTML surrounding your pictures URL is incomplete - your picture url http://img545.imageshack.us/img545/5153/duneswithpalmsrear.jpg needs to have [IMG] at both the beginning an end.
So just edit your post & type [img] at the end of the address & all will work.
I see a worse for wear P-38 on a beach holiday - just one thing to be aware off though, you image is a little bit on the large side (3648 x 2736) which means it takes a while to load & will "stretch" the forum pages for anyone looking - this starts to happen somewhere about 600 pixels wide.