agent/engine/docker_image_manager.go
func (imageManager *dockerImageManager) getImageState(containerImageID string) (*image.ImageState, bool) {
	for _, imageState := range imageManager.getAllImageStates() {
		if imageState.Image.ImageID == containerImageID {
			return imageState, true
		}
	}
	return nil, false
}
func (imageManager *dockerImageManager) getImageState(containerImageID string) (*image.ImageState, bool) {
	for _, imageState := range imageManager.getAllImageStates() {
		if imageState.Image.ImageID == containerImageID {
			return imageState, true
		}
	}
	return nil, false
}
// getImageState returns the ImageState object that the container is referenced at