"Five Engineers"

I was looking at art today when I saw a picture titled "Five Engineers" (Concept in Progress). It was supposed to have the chief engineer from each Star Trek series: The Original Series, The Next Generation, Deep Space Nine, Voyager, and Enterprise in that exact order. This places the character of Miles Edward O'Brien right in the middle, and they didn't even have him in a DS9 uniform, he was still in his TNG uniform. How is he supposed to be accurately portraying an engineer from the DS9 series while they use a picture from a preceding series?