funfly,
From FAQ
To attach a file to a new post, simply click the [Manage Attachments] button at the bottom of the post composition page, and locate the file that you want to attach from your local hard drive.
After posting, the image attachments may display a thumbnail, depending on the forum settings. To view the contents of the attachment (if it is not already displayed) simply click the filename link that appears next to the attachment icon.
or jus click "post reply" then "insert image" ( little icon that looks like a small picture of two mountains and the sun ) then allow scripst ( if requested to ) and finally "preview post". If you like it "Submit Reply".
Hope it helps.
Have a good one!