I've planned large high end events for over a decade. We always provide food for our vendors and volunteers. Here's what kept our vendors (photographers, lighting specialists, DJ/band, auctioneer, MC, wait staff, florists, etc) happy and loyal:
First, I set up a side room with several sets of tables and chairs. Simple black linens, nothing fancy. Also set up a few long rectangle tables along the wall for setting up meals and for room for them to store purses/chargers/spare lenses/etc. This room is stocked with waters the entire time.
Day before, (set up): I provide bagels, fruit, yogurts, muffins along with coffee, tea, OJ for the morning crew. Lunch is always brought in something simple like deli trays and salads or pizzas and salads. I offer sodas with lunch. In the evening, the lighting crew and I have to wait till after dark to dial in the lighting elements, so I bring dinner (always fast food burgers because that's their favorite). (Sorry for the formatting fail; too lazy to fix!)
Day of event: same breakfast is provided. Later in the day, I have a hot and cold buffet set up and ask the caterer to keep it stocked with the components of the main meal that translate to family style presentation (ie, we will be serving each guest a fancily plated individual salad, but for the vendor room they'll take the same ingredients and make a large bowl of tossed salad). This works because the vendors get to enjoy the same nice food as the guests but it's served in a way where they can help themselves when it works for them to break away, which will obviously be different times for each trade. I also always put out a large bowl of fun sized candy bars if anyone needs a sugar boost. It's a long day!
Day after event (break down and clean up):
Since most of the vendors will have had a long day, I try and make this a hot breakfast. I generally have a local favorite breakfast spot deliver an assortment of breakfast burritos and breakfast sandwiches. I have each serving cut in half and wrapped individually so it's easy to grab and go and not a whole production to sit down and eat.
It's an extra expense, but not expensive, if that makes sense. Muffin and deli trays and drinks from Costco, pizza from the local 2 for 1 place, caterer charges much less for buffet style vs. plated. I think it's worth every penny. I am relying on talented professionals to work their tails off and it's in my best interest if they feel cared for and comfortable. I can't tell you how many times that care and consideration has been returned. My lighting crew comes from three hours away and they are so grateful they are catered for on site and I'm grateful that they happily stay into the night with me until we get the look just right because they don't have to figure out where to get dinner and rush to get there before closing time. The few times I've had day-of emergencies, my vendors move heaven and earth to fix the problem and they'll pitch in to help each other and me, going above and beyond their contracted duties, if need be.
Anyway, my long winded point is that the extra niceties pay off in spades and if your talented photographers have worked out that ensuring two meals are available for them vs. dragging along lunch bags/looking for somewhere to store them (and I think it's polite to ask for what you are already serving; I'd be annoyed to have to ask the caterer to prepare a separate meal type) then there's nothing cheeky about it and I think it's a very basic and simple request 