RE: incremental rman backup using image copy

Not sure about the naming of image copies, but it sounds like what you want to do in regards to incremental image copies is available in 10g, known as "incrementally updated backups", although I've not tested it myself it sounds swell:  

http://download-west.oracle.com/docs/cd/B19306_01/backup.102/b14192/bkup 004.htm

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