Dear weso its very simple
when u are typing your post u can see Img button on the top list.. YES it is code button..when u press it a command will show [img].. after add this command copy your image link and paste it..then press Img button again..
your image will fixed in [img] code.click on preview button to check your image..if image shows in your post then you are done..
sorry if i cant tell u in detail..but u have to try it
bye take care