Same guitar strap, same guitar and, believe it or not, same venue—both of those photos were taken at the Seminole Hard Rock Hotel & Casino in Hollywood, Florida. But the Rivers we see above is him just five days before his 44th birthday was celebrated. The former pic was him at 42.
The Rivers on the right is from 2005 and the other was taken in 2010. Looks like he got the sweater dry cleaned for its second cameo.
Obviously the one on the right is older, c'mon.
This pic of the Weezer "W" was taken in 2014. The other was snapped in 2010.
The one on the left is clearly the older Rivers. If you got this wrong, you're probably not a real Weezer fan...
A big gap here...but this photo of Rivers at 42 years old shows an aged man, whereas the other shot of him at age 34 was youthful and glowing. (JK, he always looks exactly the same.)