Most forums use a variation of BBCode.. so you'd take your signature image and wrap it with [ IMG ] http://www.rowelab.com/AquaController/rc_erayk1_sig.png [ /IMG ]. (after removing spaces.)
On this particular forum, you format it like you would inside a web page- < img src = "http://www.rowelab.com/AquaController/rc_erayk1_sig.png" > (remove the spaces)
Which yields this-
