Put another way, don't bother with the shortcuts provided by Bike Forums when posting photos from Flickr; they are redundant. Just go to Flickr, copy the whole "BBCode" and paste it where you want the photo. Then hit the backspace button to delete everything after [/img], then go to the beginning of what you've pasted, and delete everything before [img]. Then you're done.
You don't need to delete anything. Just paste the BB code.