This image couldn’t be simpler. Two colours (black and blue); four visual elements (the ground, the sky and two boys). And the boys are the same colour as the ground (black).
The key to this shot lies in the body language of the two boys. It really couldn’t be anything else because there is nothing else happening here! The taller boy – presumably the older of the two – seems confident, the leader. The second boy is following closely behind, a hand outstretched towards his older companion, perhaps seeking acceptance. This body language suggests the nature of the relationship between the two boys. But what is the reason for depicting them as silhouettes?
Well, there are two reasons. First of all, removing all detail from the boys other than their outline concentrates the attention of the viewer on their body language; and by extension, what that tells us about their relationship. We are not distracted by what they are wearing or what their faces look like. Secondly, the absence of identifying details suggests that these two boys represent ALL instances of the relationship depicted, not just this particular one.
By removing unnecessary detail, this image becomes a representation of all relationships involving an older and younger brother, or an older and younger friend.
Less, is more.