PNGS ok to use?

Hi.

This is going to probably seem like a stupid question but I have tried doing some searching and can’t figure out the right answer.

If I am using 2D toolkit, is it ok for me to create all my 2D assets in Photoshop and export them as PNG for transparency sake to use with 2d toolkit, or is that something that will increase the size of my game?

Is there a better format to be exporting to for unity?

Why not just use PSD directly, rather than exporting? The only thing that matters as far as size goes is the texture settings in Unity; the source is irrelevant (and not used once imported).

–Eric