I know the rowboat painting first appears in Breaking Bad in the fugue state episode and shows a man rowing away from his family, and then appears again when Walt is hiring Jack for the prison hit. Does it appear in any other episodes, and does it have any other meaning besides the obvious of leaving/alienation of family?
Is the rowboat painting in more than 2 episodes?
No, as you figured out already it appeared twice, once in S02E03:
Second time in S05E08
The only change in the painting was probably due to lighting, as painting seems the same.
Does it have multiple meanings?
Might be possible but I can't figure out myself neither anyone else did as per my google-fu. The only meaning I can figure out is it shows how he is drifting away from his family to reach the ship.
Maybe another analysis I found came to same conclusion:
The painting can be interpreted as visualizing Walt's own growing alienation from his family and loved ones.