A couple additional thoughts:
1. a brief description is often nice (maybe as simple as where taken/what looking at). This goes in the initial "commentary / insight" box.
2. hit enter key 4-5 times so that, when you're posting multiple pix, they will show up in the thread separated a little. Otherwise they will abut each other.
3. within the pop-up window that allows the upload, be prepared to enter something in the "description" box - however what you type DOESN'T show up in the thread itself.