My passport photo looks very different to me.

It is amazing how much you can change in quite a few years.

I'll either get one of two reactions when showing my passport to immigration. Either I get stamped into the country without any dramas or they'll look at the photo, look at me, look at the photo, look at me and/or make a comment "Is that really you?" or "Wow. How long ago was this photo taken?".

SIN agents are the funniest. They just about always have a funny comment about the photo.

Sometimes I'll pre-empt the second comment with a smile and a "yeah it's really me" comment if they're up to their third glance back and forth or staring too long.

Passport officers are trained to detect certain characteristics of people vs photos - things like the size/shape of nose, moles/freckles, the way the ears sit, eyebrow/eye shape etc. They shouldn't be worried about you looking exactly like your photo - if you did then it could arouse more suspicion for a passport that is supposedly old.

That's why it really isn't an issue. The worst thing that will happen is they'll spend a few minutes asking you some details to put their minds at ease.