There are lots of threads here with Tekken screenshots. Look around. As for Tekken Tag, I'm not so sure whether anything for that has been posted, but you could always just look on a review site or something for screenshots of that.
I am currently addicted to Tekken TT, and it is really nice that the moves use in Tekken3 can also be used in Tekken TT. And why not get a joystick emulator? It works perfectly on my system. It is really nice to use a joystick to play Tekken instead of using joypad.
Btw, i cant find the link for my old tekken 3 screenshots..