What is other bank's procedure that image deposit and loan documents for record retention. Do you keep the image indefinitely and do the research even if it is over 7 or 10 years?

Is there any way around having to do the research just because we have it on an optical which we keep instead of a paper form that is destroyed after so many years?

If you get a subpoena for records, and you have the records, you may be required to produce them. Even if they're older than you retention schedule requires.

If an examiner finds errors in loan files, you may be required to correct them. Even if the file is older than your retention schedule requires.

"The length of time you keep documents is the length of the rope you give the examiners to hang you with." Keep it as short as possible.

That applies to imaged documents, too. Find a way to delete them when their retention period is up, or be prepared to produce / correct them forever.