If photobucket doesn't seem to automatically copy the URL into my clipboard (i.e. If I am not using a device that allows photobucket to do this automatically when I click on the 'IMG' code) then I just 'copy and paste' the code from the photobucket box titled 'IMG' manually into my post and this has always worked for me.
The following pic of a Rudd was copied into this post in this way:
Alternatively if I just put the full web address of my image (including its filename) between the HTML tags
this also works.
The picture icon that appears above your post when your writing your post (2nd icon from the right) saves you from having to type the two HTML tags
so makes it a lot easier.
The following pic was Inserted into this post using this method and this doesn't require me to have photobucket either; as long as my picture is on the web somewhere which is not private.
Keith