1. A non-transitory machine readable storage medium having instructions embodied thereon, the instructions being executed by a processor to improve computing instance launch times, comprising: identifying expected traffic patterns indicating machine images associated with computing instances that are expected to be launched in a computing service environment during a defined time period; determining, using a launch time prediction model, that caching the machine images at a predefined location in the computing service environment will reduce launch times for the computing instances as compared to not caching the machine images; determining a cache layout to enable caching of the machine images in the computing service environment, the cache layout identifying physical hosts at the predefined location in the computing service environment that are available to cache the machine images; and storing the machine images on at least one physical host in the computing environment according to the cache layout.