1. A computing system for storing deduplicated images of a data object that changes over time in a deduplicating content store, the deduplicating content store having a local cache and a global cache, the computing system comprising: a processor; and a memory coupled to the processor and including computer-readable instructions that, when executed by the processor, cause the processor to: organize the content of the data object for a first temporal state of the data object as a plurality of content segments and storing the plurality of content segments in a data store; create a content structure representing content of the data object as a hierarchical arrangement of hash structures in the data store, wherein each hash structure includes a hash signature for a corresponding content segment and is associated with a reference to the corresponding content segment, and wherein a higher-level hash structure in the hierarchical arrangement aggregates a set of lower-level hash structures, such that a logical organization of the content structure represents the organization of the content segments as they are represented within the data object; receive difference information for the data object, said difference information indicating changed content for the data object for a second temporal state of the data object relative to the first temporal state, and said difference information indicating a location of the changed content within the data object; receive the changed content for the data object at the deduplicating content store; form a hash signature for each of a set of changed lower-level hash structures associated with the changed content; form a hash signature for a changed higher-level hash structure aggregating a plurality of the set of changed lower-level hash structures; determine, subsequent to receiving the changed content at the deduplicating content store, whether the changed content should be stored by searching for the hash signature for the changed higher-level hash structure in the global cache of the deduplicating content store before attempting to search for the hash signatures for each of the set of changed lower-level hash structures; store any changed content that is unique in the data store as content segments; modify the organized arrangement of hash structures to incorporate new structures for the content segment corresponding to at least one hash signature for the changed content; and incorporate the new structures in the organized arrangement of structures at a position corresponding to the location of the changed content within the data object as indicated within said difference information, thereby using the higher-level hash signature for the changed content without unnecessary searching for hash signatures for the lower-level hash structures.