first write your post
now scroll down to immediately below the submit button where it says upload attachment.
now click browseand select a picture/file from your computer.once you have done this
you must now clickadd the file a box will pop up and the file will upload.
now go back to your post and place the cursor on a new line.then immediately below your post click the box place in line.you have now added a picture,well its just worked for me:D .