noun
treasured picture; secret picture; obscene picture
A rare, somewhat literary noun for a picture that is kept hidden or treasured, often with a nuance of secrecy or indecency. The exact meaning depends on context; it can refer to a cherished private artwork, a confidential illustration, or a lewd image.
彼は長年秘図を大切に保管していた。
He had carefully kept the treasured picture for many years.
その古文書には秘図が描かれていた。
A secret picture was drawn in the old manuscript.
江戸時代の秘図には猥褻なものも多い。
Many secret pictures from the Edo period are obscene.