She had also recently appeared on the other side of the camera, posing for a professional photo cradling her stomach, which she posted on the Tee-Jay Photography Facebook page.
"Not long until we meet our little girl and see my boy turn into an amazing big brother. Exciting times ahead!" she wrote.
In another post she wrote how she was looking forward to taking her business and "growing family" to "beautiful Central Otago in May".
Johnstone also volunteered for Heartfelt, a group of professional photographers who go into hospitals to take photos of families with babies who are seriously ill or died during birth so they have a keepsake of their little ones.
Dale said he had set up a Givealittle page in Johnstone's memory at the request of other photographers to give them the chance to pay their respects and donate to her surviving husband and young son.
"It is with deep regret that we mourn the passing of Janay Johnstone," the page states.
"A wife, a mother, a photographer; Janay was a wonderful mum to her beautiful boy and so excited to meet her wee girl due this month."
"She was bubbly and vivacious with a heart of gold. Janay was an incredibly talented photographer, and an absolute baby whisperer. She will be greatly missed."
Facebook user Angela Jane was among those to pay tribute to Johnstone under a post about her on the NZ Institute of Professional Photographers page.
"So heartbreaking, my thoughts are with her beautiful little boy and partner and the journey ahead," Jane wrote.
"Janay touched so many hearts with her beautiful photography, families will cherish those moments forever. Wishing love and peace for her family and friends."
Moira Clark wrote she was "so sorry to read this today..taken far too soon".
A public notice said: "Our darling Janay and her precious pepi will be resting at her Wattle Downs home, before their journey to the Far North (date to be confirmed)."
