Just the same as any other photo storing service velvetelvis.
Pop your piccies in a folder with permissions set to 'Everyone' and post them into the forum as you would any other picture.
(Do a properties on the picture and copy the url into your forum image tags)
Not sure why coffee said it's a pain, it's just the same as posting from any other service like flicker or photobucket etc
Do a properties on Spike and you'll see the SkyDrive URL for his piccy. (Very Long)