Use the manage attachment button in the additional options box under the dialog box to browse your computer to upload a picture into the thread. Or under FAQ it has instructions on how to link to your photo album and insert the picture in the text area. You can copy the HTTP line and click on the little yellow mountain Icon above the text box where you typing and insert it that way
To post this I visited your photo album clicked on the pictures and copied the line below the info. Then I pasted it into the text box.
You can just load the picture from your album or click on the manage attcahments button then the browse button and upload it from your computer as an attachment .