a place for zinesters - writers and readers
i struggled with this a lot the last zine i made, but ultimately i chose black and white. it's classier and makes all the pages look better together.
i don't think i'd pay an extra dollar for a color zine.
i think your best bet would be to make some kind of insert, perhaps glued on, with the color photograph(s) on them, printing the rest of the zine in black and white... that way, you don't have to copy pages and pages of mostly black and white content with one color photo and waste money. you could even put the pictures on glossy paper and make them look really good. plus, having things glued in gives it a nice homemade feel because you put work into every copy.