The experienced forward makes a quick return to Ewood Park, after his three-month loan spell with Rovers at the end of last term.
Blackburn boss Gary Bowyer was delighted to land the 31-year-old on a free transfer following his release from Queens Park Rangers.
"He's a player who has huge experience and is a proven goalscorer at this level," Bowyer said.
"He feels he has some unfinished business with the club and is hungry to succeed.
"He will add a different dimension to our attacking options and he is the right character we want to have on board."