The Western Australian Criminal Code section 221BA defines an “intimate image, of a person” as:
a still or moving image, in any form, that shows, in circumstances in which the person would reasonably expect to be afforded privacy —
(i) the person’s genital area or anal area, whether bare or covered by underwear; or
(ii) in the case of a female person, or transgender or intersex person identifying as female, the breasts of the person, whether bare or covered by underwear; or
(iii) the person engaged in a private act
Subsection 221BD(2) defines the offence of distributing an intimate image (without consent). But unlike some other Australian states, the Western Australian Criminal Code does not seem to define an offence of recording an intimate image (I am using the term “record” in a generic sense, to refer to both still and moving images).
A WAtoday story from 2017 described a case where a person allegedly recorded under another person’s skirt without that person’s consent, and was charged with “indecent act in public”. This is an offence defined in section 203 of the Criminal Code:
A person who does an indecent act —
(a) in a public place or in the sight of any person who is in a public place; or
(b) in a police station or lock-up,
is guilty of a crime and is liable to imprisonment for 2 years.
This seems to be a specific case of recording an intimate image without consent; it is not clear whether it generalises to other intimate images, or what the result of the charge was.
All jurisdictions within Australia have passed laws making it illegal to take upskirt photos in public places without the person's consent.
But it only cites an apparently outdated story about “draft uniform national laws”; the current laws in Australia are certainly not “uniform”.