Image Services does not support secure deletion of document content.
A single Image Services disk cache might have multiple copies of a document because of its transient nature. For example, when a document is moved out of cache, the cache space is returned to a free space pool, but the space is not scrubbed. When the same document is retrieved, it might use the same free space. As a result, there might be several copies of the document in a cache. The copies in free space are not managed by Image Services as document objects but are still on magnetic disk.
The primary cache object is not removed immediately if the Image Services delete capability is used (DOC_delete_documents). It is assumed that the cache object is aged out if it is in cache. The cache object is removed immediately if the system is a cache-only system.