How to change particle shape in SOP nodes

Q1. How to change particle shape into PNG file type in SOP nodes especially in this situation I attached?

Hi @hakyeong_choi,

you can render the particles as point sprites and attach a texture to them.
Instructions on a basic Rendering Setup can be found here:

More particular dealing with particles and pointsprites, perhaps this can help - while older the basic concepts still apply:

Hope this helps