If you look below the comment box on your screen, you'll notice that there's an area that shows the correct way to write codes to put up pictures on the site. (And various other codes that work on this forum.) 

There are two ways you can post photos:

[*img=http://example.com/flower.jpg]

or

[*img]http://example.com/flower.jpg[/img] 

(Just remove the * from the beginning of each code.)