@Tove
To add a picture go to an image hosting website [ I always use this :
http://postimage.org/ ],
select your size ( choose 640*480 for message boards ) and upload your image there, you'll get a link

look for "direct link" and click on "copy to clipboard" (circled in red)
then on this forum, click on this tiny monalisa icon

paste your link between the "img" tags.
thats it. your image will appear.