보고는

after seeing, having seen

→ 보다
보 seem, appear + 고 And + 는 Topic marker
verb Rare #27,602
after seeing, having seen In a negative construction, 안 보고는 can mean “without seeing.”
KO: 그 사진을 보고는 웃음이 났어요.
EN: After seeing that photo, I laughed.
Conjugation of 보다

이틀 전에 보고는 통 못 봤어요

I saw them two days ago, but I haven't seen them at all since.

— 와호장룡 (2000)

신문 몇 장 보고는 저런 진술 못 한다고

You can't make a statement like that just from reading a few pages of the newspaper.

— The Chaser (2008)