Would like the ability to either pull from CDI source fields for thumbnails for example the way the CDI for Naxos can use {{control/sourcerecordid}} to build the link for online access. We need to be able to use this same field to pull in the thumbnail automatically. Alternately or in addition another option would be to allow additional logic from another Marc field to determine whether a field should be used. e.g. Use 035a for $$LinkingParameter1 IF 040a = Naxos.