"A house named "Johnsville", location unknown". Source: Leigh McKinnon posted this to "Australia - Vintage Photos of Cities and Towns in Australia Facebook Group", 10 April 2018.
The photo was later identified as being at 74 McCracken St, Kensington, and the woman and boy to be Jessie Douglas and her son John.
The woman's dress dates to about 1880, and the boy appears to be around 12-14, so I am a little doubtful about the identification of the Douglas mother and son. By 1880 John would have been 24, and Jessie 66, neither age applying to the two in the photo.
The house, on the other hand, does conform with the shape of the front of the house shown in the MMBW plan from 1901, detail below, though of course many others did. I have not yet seen any other image of the house, so that is also open to question.
The Douglases weren't in the house as early as 1880. The 1884 Sands & McDougall Directory shows two houses between the school and the Wesleyan church, occupied by Charles Dalton and J Rossthorn.
See the Time Travellers website for further details about "Johnsville". Please get in touch if you can shed any light on the house or the people in the photo.
Alex Bragiola advises that the house was built circa 1882 by James Rawsthorne a local builder, according to the rate books, before the Methodist church on the left was built. Presumably the J Rossthorn mentioned in the Sands & McDougall directories was actually James Rawsthorne.