I found a youtube video on this a while ago but I can’t find it again
It showed you which way to align your texture plane so that no matter how you look at it, the texture projects towards the camera, as in, perspective angle not applied
Add textured plane, unwrapp it, add image.
Go in edit mode and rotate along Y axis by 90 degrees.
In object’s material settings find “Game” parameter and under that find a property called “Face Orientation”. Set it to “halo”.
Done;)