Brandon Blackstock Poses With Daughter in Photo Taken Weeks Before Death

Brandon Blackstock was fighting a difficult cancer battle before his death ... but, you could hardly tell a couple weeks ago when he was grinning big in a photo with his daughter.

Savannah Blackstock Lee, Brandon's daughter from his first marriage to Melissa Ashworth, shared a photo on Facebook last month standing alongside her dad with a sprawling wilderness behind them ... and, Brandon's arm is slung over her shoulder.

Blackstock's got his Uggs on ... bringing his leg up on a bench Captain Morgan-style. Savannah's totally beaming in the pic -- and, from the outside, it seems like nothing's wrong. She captioned the picture, "Back home to the mountains & my daddy."

The pic was posted to FB on July 20 -- and, Blackstock died early Thursday morning this week after his fight with melanoma.

Blackstock's ex-wife, Kelly Clarkson, postponed her Las Vegas residency earlier this week to be with her children while Brandon was sick... but, we didn't know just how sick until Thursday.

BTW ... Savannah is expecting her second child -- so, her life is full of change right now.

Blackstock was 48.