'Sister Wives' Janelle Brown Shares Last Family Photo Before Son's Death

Janelle Brown is remembering happier times in the wake of her son, Garrison Brown's death -- posting a photo of the last time her whole brood was together.

Just a couple days after reflecting on Garrison's passing -- which occurred earlier this week -- the "Sister Wives" star shared a sweet family memory ... throwing up a pic on her social media that featured all six of her kids, whom she shares with her ex, Kody Brown,

The picture, Janelle says, was from Christmas ... and she wrote, "I had all my children together last Christmas. It was amazing as it's hard with everyone's busy lives to coordinate time like this. I am extremely grateful now that we had pictures taken."

The holiday allowed for Janelle to snap a pic of herself with her kids and grandkids -- the image marking the last full family photo for the reality star ... and obviously more poignant now in the wake of Garrison's passing.

The new upload marks Janelle's return to social media after announcing Garrison's death, who died by suicide on Tuesday -- this after she confirmed that her son had passed away.

We broke the story ... Garrison -- who appeared alongside Janelle and Kody on "Sisters Wives" -- took his own life at his home in Flagstaff, AZ. Flagstaff PD told us that Garrison's brother Gabriel was the first to discover him.

While we're told that Garrison died by a self-inflicted gunshot wound ... an investigation is still reportedly underway. Cops spoke with Janelle the day he died -- and she alerted them to alarming texts he'd sent to people they'd worked with before, and that raised red flags.

Garrison is survived by several family members -- as the Browns were famous polygamists before Kody's respective splits from wives Meri, Christine and Janelle over the last couple years. He was only 25.

RIP