The nice part about Docker is the images are composed of layers, so you only have to re-download a layer when it changes. In practice, we pull all of our base l

The nice part about Docker is the images are composed of layers, so you only have to re-download a layer when it changes. In practice, we pull all of our base layers when we bake our AMIs, so spinning up a new instance is pretty quick and each new deploy only has to update the top layer that contains our code. Honestly, the only issue when it comes to image size is the initial developer pull either when they onboard to a team or when they bork their boot2docker install (which, disturbingly, happens way too often).