What's the best way to import characters ?

Hi,
what’s the easiest & most optimized way to bring a 2D character sprites into unity?
Is it by using a PSB photoshop file with all the layers, or
just throw all the character assets into unity & create 2D sprites using the packing tag ?
Does the PSB weighs more, inside unity?
Thanks in advance.

the best way is to save as png and then drag into unity