I think you got the tag wrong, in my experience your're suppose to put the image address into the center
Correct, the image URL is supposed to go between the bracketed commands, (bracket)img(bracket) address URL (bracket)/img(bracket)
.jpg or .jpeg tends to work whereas .png gives me fits.
(Some may disagree with my recommendation to use facebook but I never had issues) it was discussed earlier
Yeah, that's a no from me dawg. I use FB on the daily (though I'm iron-fisted in what info gets shared) but I can't in good conscience send anyone to Schmuckerberg's site to use even in just an image hosting capacity. I'd refer them to Imgur or even Flickr if need be.