To post pictures.
1) Hit the Preview button on the bottom. (Open up the "advance" posting screen)
2) Hit "Additional Options"
3) Add your attachments. Note they need to be an internet friendly file format. JPEG or such.
4) click post
You will get an error if it can't post the picture, and it should give a reason why it can't post it.
Thanks for that, learned me som'n