well, it's great to confuse your opponent. plus it makes your opponents feel like shit when they realized they made a bad fold and puts them off their game.
Honestly, I think this one of the very very few times I will show a bluff. If I know my opponent has the tendency to tilt and he thinks for a good amount of time and then folds, I know he had something. I'll show him just to let him know he made the wrong decision, not to alter my table image.
You should keep in mind that I bluff a lot. Whether it be with Cbets or when I sense weakness, I bet and raise a lot. So, people instinctively know I bluff a lot anyway. I don't need to show my cards to let them know why, how, or how much I bet.
As a rule of thumb I like to follow, I don't do anything in particular to purposely alter my table image. I try to determine what my image is naturally and benefit from that. I play the players at my table and I alter my play according they and their styles. In general, if the table is loose, I will tighten up. If the table is tight, I will loosen up, etc... THEN, I try to THINK about how the table naturally sees me. The individual players matter a lot too.
If you show your cards, remember, you show everybody. Some players you want to know you bluff, but some you don't. Some players will let you cbet bluff them all night long and never give resistance unless they make a hand. I don't want that guy to know I am
bluffing him.