Objects and Flat Images/PNG Sequences always face the user/camera

So I'm trying to recreate smoke in my scene and I'm testing out a sequence of transparent .png files to show the smoke moving. It looks great when face on but as you move around the .png sequence you then see it's a flat plane. The ability to get that plane (or 3D object) to turn and face you at all times would then fake it to make it look like it's really there from all angles. I'm thinking that it would need to pivot around the y axis only (but an option to choose axis points would be useful). Many thanks!