javascript - Append string using regex -

hi i've been trying find , replace width & height of image using following url

http://res.cloudinary.com/chathura-rupasinghe/image/upload/v1453573679/manhattan_logo_kd7ts8.png

into

http://res.cloudinary.com/chathura-rupasinghe/image/upload/c_fill,h_80,w_80/v1453573679/manhattan_logo_kd7ts8.png

notice c_fill,h_80,w_80
need append c_fill,h_80,w_80 between upload/ {mystringgoeshere} / how do ? im bad @ regex.thanks