If a sub is actually carrying Tomahawk-displacing drones, it will be for very tactically important reasons.
It's possible the photos are really for public consumption, and the drones are loaded into quad- or six-pack tubes, much akin to a revolver pistol. So, maybe SIX drones are displacing one T-Hawk. Besides, a 2000-mile range Tomahawk could be reconfigured as a very large, very expensive drone of sorts, sans warhead, or with droplet munitions packages to take out targets of opportunity so long as their is fuel onboard and as long as their are comms links to the missile, or some AI programming telling it how to deal with a decided-upon "target-rich environment" in advance.
The drones probably need be in only around 6 inches in diameter radial tubes. And, given the length of a VLS tube, it is possible that some drones could be only 2 feet long, meaning that possibly 3-4 vertical stacks could be used. So, if a huge net/mesh needed to be built for a tactical picture that for some reason U-2s, AWACS, satellites, or P3 ASW planes could not configure in a timely manner, a suitably-equipped attack boat MIGHT really have not simply ONE single large drone per silo, but maybe 4 or 6 per ring, and maybe 3-8 rings, meaning 12-48 drones. Simply fire the top ring first, and every subsequent launch could then either be the most immediately-below position's ring or alternating between an upper ring and a next-below ring so that multiple vacant rings up top can be exploited. The drones then could either be directly fired from all the way below, or moved up by some type of mini-ram to make the acceleration path in the sub as short as possible.
Mind you, this is just stuff I'm making up as I write this, not pre-planned before writing. The serious drawback to my idea is that once the rubber/water-blocking membrane is blown off, water will deluge the silo. That much water weight could rupture the walls of any adjacent silos. But, as I think I can recall back into the mid-80s, from looking at magazines, those 3 to 6 VLS tubes could optionally be made as each carrying 3-6 mini tubes. Of course, the main tube's diameter is not as large as the ICBM/Trident silo tubes. But, one can still imagine that 12 drones can build a better mesh/grid tactical picture than one, especially if there is a need for a self-healing eye-in-the-sky network. If the launching boat is attacked, shadowed, or harrassed, it probably could shift tactical control of the drones and the mesh to a back-up boat. Hence, "Wolfpack, anyone" in the subject line. Of course, it would be a very-spread-out wolfpack since the ranges and speeds of such boat's weapons are vastly greater than the German U-boats and wolfpack fleets of the past.
Also, with so many on board, they can be various in model type, range, and maybe even have an ability to drop a sononbuoy or two. These could offer stealthy relay advantages of some sort. With such a number of drones onboard, the probably would not be a real reason to "recover" the drones. They could be designed to be "biodegradable", not for "green" reasons, but to ensure that if they ditch- and they will at some point -- feet wet, then their dissolving could mitigate risk of "enemy" capture and reverse engineering, meaning a reduced incentive to put lives at risk trying to recover such highly-classified-likely devices from defended territories Once they go feet dry, though, some sort of self-destruct/auto-immolation might be desired, but might conflict with safe handling and storage/stowage aboard a sub.