If you want to upload a small image here, you can click on
Additional Options... which is below the Message box. (Not in Quick Reply.) The images will show up underneath the message. If uploaded that way.
If you have an image already online, like on PhotoBucket, you can include the image in your Message by copying the URL of your image from PhotoBucket, then pasting it in this message, highlighting it, and clicking on the image button.
It looks like you've already got it figured out on another thread. For everyone else, I hope that this is clear, but if you have a question, feel free to ask.