In these 10 years since launch, they could have precomputed every possible picture, hash them, and then the probe could have simply sent the hashes instead of the full size pictures.
Just for fun, let's see what it would take for them to pull this off. The LORRI image sensor is 1024x1024 pixels with 12 bits per pixel.
So the number of distinct images divided by the timespan available gives 2^(12*20) / (10 years) = about 5.6 * 10^63 hashes per second.
Let's say you had a CPU capable of computing one such image hash per nanosecond (very optimistic), you'd need 2^(12*20) / (10 years) / (1 nanosecond) = about 5.6 * 10^54 CPUs to pull this off.
For comparison that's an order of magnitude or so more than the number of nucleons in our earth.
If those CPUs consumed 50W of power computing these hashes (again very optimistic), the entire project would consume 2^(12*20) / (1 nanosecond) * (50 watt) = 8.8 * 10^64 joules.
For reference that's two orders of magnitude more than the total mass-energy (including dark matter) of the Virgo supercluster, the supercluster which contains our Milky Way galaxy.
Unless I messed up the calculations that is...