Generally, your triceps get worked out more than your biceps, wether you like it or not. (ie: you use your triceps during chest workouts, thats why many people do triceps and chest on the same day.) .. your bicep does like kinda small... but it could be the pic too, maybe give this a try.
here is my routein:
tricep pull down (cable machine with 90 degree bent metal grip)
easy bar arm curls
tricep extension (cable machine with handle, one arm a time)
straigh bar (using squat bar) curls
'skull crushers'
preacher curls (using the bent bar that you grip and your hands are verticle... whatever it's called )
supersetting them all of course