Nope, we can't do that - no option.
you can post pictures by either:
saving them to your computer, then use the attach files button below the chat box.
Or, if you find one on google, you can right clich it, save image link, come back here and hit the picture icon - then there's a little link icon in that box, push that and paste in your url and it should also come up!
Let me know if you have any more troubles and i'll suggest other ways.
Sometimes people block their images from being bhotlinked (not often, but i've had trouble with some)
Hope this helps