1. ps used by friends circle means "by the way". The source of this word is not the abbreviation of PS(PhotoShop), but the abbreviation of postscript, which means: postscript (signature at the end of the letter), and; Supplementary explanation (after the text)

2.PS generally has two meanings: AdobePhotoshop, referred to as "PS", is an image processing software developed and published by AdobeSystems; Ps is the abbreviation of postscript, which means postscript. By the way, it is a supplement.