How do I change the collision polygon for particles?

hey guys,

I'm pretty new to the tool so I faced this problem with the particles. Looks like the collision area is much bigger than the actual sprite.. how do I change this so the collision = sprite size?

PS. the sprite image is already cropped.

It's made to be as fast as possible, so collisions are excluded.

If you need independent particle collisions, make your own emitter with sprites.

Bullet behavior works well for this.