In addition to grantor/grantee and tract indexing from 1995 forward, LandShark has document numbers in this system going back to 1979 starting with document number 279497; so you can access images by document number through this system if the date range is betweeen document number 279497 to present.

ArcaSearch has the abstract and Torrens tract indexes from the 1850s through 1995, so it interfaces with the data we have on computer as far as searching tract indexes or platted descriptions.  It also has all but the newest plats imaged (some of those are also available in the LandShark system).  The link to ArcaSearch is http://gov.arcasearch.com/usmnfre/.