Welcome aboard! Glad you are enjoying the game and getting what help you need from what's available here.
To add a signature (tag line) to your posts, click on User CP at the far left of the nav bar above where all the posts are on this or any other thread page.
When you get to the User CP (Control Panel), you'll see a section running down the left of the page under Your Control Panel.
Look under Settings & Options and click on Edit Signature, then you can create a signature that will appear at the bottom of all your posts.
FYI, really huge pictures and seizure-inducing animated gifs are generally discouraged, and you should follow the basic forum standards for your sig as well as your posts... but if you can see all the other signatures that our members use you'll have some idea of what's acceptable.
