You posed wrong in 1st pic too - hands clasped makes shoulders look wider, very few can pull off the hands apart (Arnold?) most muscular. That also comes with experience - how to show off strong points and hide weak points. Your clavicles did not get wider in between, but compare the two pics and one pic looks like you have way wider shoulders.
Sadly, presentation is a lost art nowadays, said the 31 year old ex schmoe.