In Japan it's backwards, text board is huge and image is very small. Futaba's traffic is about the same as 7chan's. 4chan would be the biggest board after 2ch although 2ch's traffic is 3 or 2 times higher then 4chans.
http://www.alexa.com/

> Traffic Rank for 2ch.net: 294
> Traffic Rank for 4chan.org: 605
> Traffic Rank for 2chan.net: 3,100
> Traffic Rank for 7chan.org: 7,342
> Traffic Rank for 12chan.org: 9,162
> Traffic Rank for fapchan.org: 20,426
> Traffic Rank for 420chan.org: 38,352
> Traffic Rank for iichan.net: 54,504
> Traffic Rank for wakachan.org: 69,924
> Traffic Rank for 4-ch.net: 280,267 (lawl)