Racing Victoria issued one charge each against Jamie Kah and Ruby McIntyre after a probe into pictures of the pair and greyhound trainer Jacob Biddell.
The images, depicting the trio along with what appears to be white powder, began to circulate on social media last month.
Stewards allege McIntyre recorded Kah using an identification card to arrange a white powder substance into three lines during a gathering at Kah's home in June.
Racing Victoria said the perception among those commenting on the social media images was that the trio were using an illicit substance.
"The stewards allege that Ms Kah and Ms McIntyre's conduct, as outlined in the particulars, was prejudicial to the image, interests, integrity and/or welfare of racing," it said in a statement on Friday.
After the photos were published, Kah said she was focused on her recovery from a fall at Flemington in March.
The fall left her in an induced coma for several days with bleeding to the brain as well as a broken wrist and foot.
"I am working hard to get back to doing what I love, and that is being a passionate and successful jockey," the 27-year-old wrote on social media.
"I will continue to focus on my physical and mental health and making a full recovery so I can return to racing and be the best person that I can possibly be.
"I won't be making any further comment."
The charges will be heard by the Victorian Racing Tribunal at a later date.
Kah rode more than 100 metropolitan winners in the 2020/21 season to become the first female to claim the Melbourne jockey's premiership.
She was among five jockeys suspended for attending a 2021 Airbnb party in breach of Victoria's COVID-19 restrictions.
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