Assuming you use a windows PC, when you're looking at an image hosted in your fb profile (full size) right click it, depending which browser you use it'll have something like "copy image URL" (chrome) or "copy image location" (firefox) or "why bother just kill yourself" (internet explorer) ... wait no I think with IE you have to right click it, choose properties, highlight the URL listed there, then copy it either using the right click context menu or ctrl+c <img src="/forums/images/graemlins/rolleyes.gif" alt="" />

anyway then you can use the image tag in UBB to post yo shizzle.