Android's flickr app doesn't have a share to bbcode button, thus images cannot be easily shared on your preferred forums with tapatalk or directly on the forums web page.
Flickr2BBcode LITE adds an option to the share menu found on flickr app that copies the bbcode of the shared image on the clipboard, this way you can paste it on any post of your chosen forum, should it be in tapatalk or other mediums.
By default, the 800px BBCODE is copied to the clipboard.
Photos to be shared must be in public mode, private photos cannot be shared.
The difference between the free LITE and paid versions of the app is that the free contains ads while the paid one is ads free and offers options to customize the generated bbcode, like size and exif values to be shown.