Spot the main difference...
(apart from the bikes)
(apart from the bikes)
Several... it depends what you mean by or think is 'the main difference'. Their shirt colors, styles, and accessories/badges are different. There's a woman in the second one, and only men in the first. The people in the second photo seem to be a bit heavier set than the first (apart from the lady). I could keep going, but I'll stop there.