Including an image
[img]http://www.bbcode.org/images/lubeck_small.jpg[/img]
Resizing the image
[img=100x50]http://www.bbcode.org/images/lubeck_small.jpg[/img]
Making the image clickable (in this case linking to the original image)
[url=http://www.bbcode.org/images/lubeck.jpg][img]http://www.bbcode.org/images/lubeck_small.jpg[/img][/url]
Resizing and adding meta information for the image
[img width="100" height="50" alt="Lubeck city gate" title="This is one of the medieval city gates of Lubeck"]http://www.bbcode.org/images/lubeck_small.jpg[/img]
In particular, for an image, I want to store a "small" (< 640 horizontal) image and a "large" (1024 x 640) image in my Flickr account... post the SMALL image in the forum post to save on bandwidth and make it easier/better for the board, but clickable / linked to the large image.
The first and third ones yes, the second and fourth no.
Two ways to test such things:
1) Type in as if you're making a new thread/post and then press the "preview" button instead of the submit one (if your code works then it'll work in the preview).
2) Make your post and/or thread and try it. If it doesn't work, as long as your post is the final one on the list (ie as long as no-one has replied to your post in the same thread) then you should see a little box in the top right hand corner with X in it (to the right of the quote and edit buttons). You can use that to delete your own post (and thread if it's the only post in the thread).
So currently I can delete this post as it's the final one in the thread, but you would no longer be able to delete your one above as mine now blocks it. But if I deleted mine then yours would become the bottom post in the thread and you could then delete it (and the thread in this case, as it'd then be the only post).
.