Resource use reading from file system

I built a quick & dirty photo gallery that reads the file system to display filenames of all the images in each folder. As traffic increases, will it save system resources if I have a cron job write include files with the contents of each folder? Is the processor taxed much more to read ~10 files from a folder, than to read a single include file? I know it's less, but I wonder if the difference is really all that significant.