I get what you are trying to do but I just don't see this being a useful option at all:
(1) If your printer doesn't clog even after a year, you don't need to try to use random photos as "unclog sheets".
(2) If the printer does clog, you should be using the unclog sheets and not photos.
(3) If you are trying to so something like prevent a printer from printing a cleaning cycle after 24 hours, printing a half sheet unclog on copy paper makes sense.
In the end, no one is going to want to wait 3 days to get the photo on page 3 and you'll end up printing throw-away photos that no one wants, wasting photo paper when you could just print an unclog pattern on a half sheet of copy paper. The unclog uses WAY less ink (and balanced ink usage) than a photo anyway and you can print them on copy paper. Then you can print the photos you want when you want them. Even in a case where you print a lot of the same photo(s) for stock, if you are circumventing a 24 hour cleaning cycle you'd be better off using a purge sheet that balances ink usage, uses very little ink, and uses throw-away copy paper so you can be sure you are doing enough to circumvent that 24 hour cleaning cycle (they put that there for a reason) and just print what you need when you need it.
In addition, you can already print one photo a day using the mentioned spool and cool option which should be adequate for this niche workflow.
Mike