Would not be at all shocked if the first picture was taken before any kind of workout and the second picture was taken immediately post an intense workout where the players still had their "pump". Still impressive gains, but as a fairly avid lifter, I can tell you I look a hell of a lot more jacked up post workout than I do crawling my butt out of bed in the morning.
A combination of hard work, a great program by Balis, substantial supplementation, an emphasis on leaning out, post workout "pump" and a different zoom on the camera is likely the formula for the massive transformation.
Regardless if it's a tad misleading, mentally, it has the players believing and that's all that really matters. "What you believe, you can achieve". If Balis' program is something the players believe in, that consistently challenges them and is something they are willing to put 110% of their effort into, the results will come and that will translate to confidence, which a is key ingredient to winning.