you could upload the image to imgur or something
then cope the image link (right click the image then click on "Open image in a new tab" or it should say something similar.
Then copy that website link.
My profile pic for example is :
zarpgaming.com/media/kunena/avatars/resi...r282061501111748.png
So what i do is add the [.img][/img] things (remove the dot in the first bracket)
and you get this :