I don't think having a tight/agressive table image is a problem at all. You just have to know how to take advantage of it. Once you've established your tight/aggressive image, you can take advantage of it by opening your range up a littel bit. Your opponents will give you credit for having strong hands because of the image you've cultivated. You can also use your image to steal pots away from limpers. Say, for instance, a couple of players have limped into the pot in front of you, you can throw a raise (3x + 1x for each limper) at them. If they're not strong enough to raise, then they probably aren't going to want to call a raise, especially from a tight player. You don't want to get carried away. Playing too many hands can be a dead giveaway that you're up to something. After all, you can't always have a hand.
Don't be afraid to continue post flop. Say you get involved in hand with J-8 suited or some such. You miss the flop, but a Q hits board. FIRE! If they've missed as well, they're likely to give you credit for the Q as it would probably be a card that you would likely be holding given your normal range. Losing a hand here and there isn't necassarily a bad thing. You want to be winning them, of course. But you can think of it as a sort of win/win situation. If you win the hand you get the chips. If you lose one, then it makes the other players think that you might not be so tight after all, and they will be more willing to play with you. If you feel like you're starting to get played with or played back at too much, you can revert right back to your tight style until you've resolidified that image again.
Mix it up a little bit too. Position is important and should always be taken advantage of. Here's something to think about throwing in the mix, though. Consider those marginal hands, that you might be tempted to see a flop with, but your normal style doesn't allow for this. Step outside the norm and open for a raise with that hand (if you're playing, you should be raising). On top of that, let's put conventional wisdom on hold for a minute and say position doesn't matter. In fact being OOP might even be better, as your opponents will assume that a tight player is not going to raising OOP with a marginal hand. Once again this creates that win/win situation where you either take down the pot, or if you lose you lessen that tight image up enough that you will likely get more action when you revert back to your tight/aggressive style.
I'm not saying go from TAG to LAG. I'm saying open your game enough to take advantage of your tight/aggressive image. Stay primarily tight. Tight is your 1st base. Take as big a lead away from that base as you feel comfortable with, and look for an opportunity to steal. If the pitcher throws over to 1st. Hustle your butt back to that base.
Good luck.
