A method and system for image instance mapping is provided. The method includes receiving from change agents on virtual machine instances periodic monitoring data indicating changes for each virtual machine instance. The periodic monitoring data is analyzed and unique updates are applied to the virtual machine instances. High level semantic updates to the virtual machine instances are identified and updates associated with a golden master image are tracked. High level semantic updates to the golden master image are identified and in response, a version tree configured to track drift of each virtual machine instance with respect to golden master image is maintained.