Yes, you can put an image in the same post if you turn off URL parsing (well, certainly if you use HTML like I have in this post, and I guess vBB tags would work the same) - all that does is put the vBB tags on either end of the URL, so far as I can tell, and shortens the URL so it's not so horribly big (in the case of PI URLs).
As... (the URL is just a random PI one, nothing important)
http://communities.msn.co.uk/_Secure/0OQAAANQUiVnxao5LMLzJ
*uv3papJRqj84p27lpzE7Ru87JPvTSI3yTsmSQThteEjyuS!
pOqUbvmS0ZvCcUYH4CKrW*yUdqvM/fox_col_exp.gif
Edit: Yuck, scrollage... *goes and puts some linebreaks in*