The easiest way is to go to Edit Options from the User CP and scroll down to nearly the bottom. Under Other Options there is an option for using vB quick links. Click the "Yes" option. When you reply a thread, click "New Reply" instead of using the quick reply box, and there will be all the smileys to the left.
I don't really know what you mean. If you mean the green thing that I've circled in the picture below, then that just means that the thread has new replies since last time you visited the site.
Also, to pre-empt your next question, you can upload pictures if you host them on a site (such as www.81X.com or www.villagephotos.com, or at Rajah's site - a link for this can be found in the Graphics Showroom) and then have to hotlink them to posts or your signature. Only Mods can upload pics.