Choose the caption bubble to begin. If you want to upload a custom bubble or alternative image then submit the caption first, then edit the comment and attach a "Place img". Once the image is approved you can use it by editing the caption again.
Sean (left side) was our WCG guy for the entire event, we had to make sure he knew where we were at all times, even going to the toilet... the other guy I forget his name, but he was our camera man throughout the event. Both good guys.