Below the Quick Reply box under each photo is a button labeled "Go Advanced" which opens the WYSIWYG editor. The problem (as I see it) is that pushing this button before entering any text only refreshes the page. You must first type some text into it and then push the button to open the WYSIWYG editor.
In case it's only me see:
http://www.japan-101.com/photos/show...cutoffdate=all