Now if you are linking from another site, make sure they don't consider it stealing their images, because if you do and they change the image to lets say PORN you could end up in trouble here.
Linking with code:
[img]http://upload4.postimage.org/1195248_fb2532cc31cc66d73f81503fa6666301/MammothInvasion108.jpg[/img]
Linking an image in this manner will get you this:
If you use MCBB's image generator make sure you have below the maximum size allowed it is 100 kb then follow these simple instructions.