It will probably be harder, but not as much harder as you might think. Handling new complexity requires new brain structures, which in turn uses up energy that could be spent elsewhere. Other things being equal, the brain tends to re-use as much as it can. There is some evidence that the brain re-uses the same structures for visual memories as it does for visual processing. I wish I could quickly find you a reference.
Richard Granger has some good articles on brain structures, and he is a very accessible writer. (For a start, Google for his paper "Engines of the Brain".)
Of course, take the "brain re-uses useful structures" hypothesis with a grain of salt. There is some evidence in for some brain structures, but by no means conclusive.