Photos on PPRuNe have to be 'hosted' online on another site, typically Yahoo's Flickr, Google's Picasa .. or one of the many additional photo-hosting sites.
If its just a 'one off' and you don't want to go trough the rigmarole of setting-up a photo-hosting account, email the image to
[email protected] and I'll mail you a link which you can use for your post.