In previous years there were alot of jokes about the colored shirt so this year they photoshopped it. A logical reaction. The reaction that, “oh this is not emes”, absurd.
Like a commenter said above, one person obviously different from the rest will just draw attention to that individual. The purpose of the picture is to to show the Yeshiva as a whole. There is is the intitution as a whole and the individuals who are parts thereof. This was a picture of the Yeshiva as a whole and not intended to focus on the individual talmidim who make it up. (Do not get started that yeshivas should treat talmidim as individuals, that is not what this is about at all.)
I do not know about filling empty seats, however what I remember of the Yeshiva is that there are not empty seats and the picture must have been taken at an odd time.
As an aside, there is such a concept of uniform. A unifrom identifies as to which group a person identifies themself with. Nowadays, almost all Yeshiva Leit wear white shirts and dark pants. To dress as such means to identify with that group and to specifically dress differently means to exclude one’s self.
The color of the shirt does not make a person better or worse, however by taking pains to be different, the person seeks to segregate themself from the group.Every one has unique strengths, but they can consider themself as seperate from the whole or, they can use their uniquiness to enhance the group. That is why, although a uniform does not make an individual, it is looked at as indicator of their own perception of how they relate to the group as a whole. When individuals seek to sepearte from a group or join a group, one of the first things they will do is to change their mode of dress. And this is is not solely among the heimish, this cuts across every facet of society.