Attach them to a post.
Click on the "Go Advanced" button under the reply box. It's next to the "Post Quick Reply" button. When you get to the advanced screen, scroll down to the middle section titled "Additional Options." In the middle of that section is a button labeled "Manage Attachments." Click on it. A pop up window will open, the process should be fairly self explanatory after that.
"As I walked out the door toward the gate that would lead to my freedom, I knew if I didn't leave my bitterness and hatred behind I'd still be in prison."