The 25 year old man was detained on suspicion of voyeurism and possessing indecent images of children.
He was released on strict bail conditions to be interviewed again at a later date.
The incident happened at the Aurora complex in Bangor in August.
Constable Adrian Bell said at the time: “Around 3pm on August 15, a woman was in a communal changing area with her two sons, when one of the boys noticed that a mobile phone was being held over the side of a cubicle.
“The boy alerted his mother to this, and the mother challenged the male holding the phone.
“The male left the changing room.
“The man is described as aged between 20 and 30, with swarthy skin, heavy dark stubble and short jet black hair.
“He is around five feet eight inches tall, and at the time was wearing red shorts with a darker red stripe up the sides, a grey T shirt with a logo on the left side and Adidas trainers. The phone was described as purple and from the maker Samsung.”