I ran this Roman denarius .JPG file through e-Timestamp.com/Digistamp's service. This X.509 certificate uses SHA-1 with RSA to prove that the image's hash was seen by DigiStamp on September 8, 2008.
Unfortunately DigiStamp only certifies this until May 21, 2010 so I'll have to sign it again (or perhaps I'll sign a combination of today's certificate and the image again) by that date.
I wrote a short piece for The Celator suggesting that coin collectors and dealers voluntarily use a system like this to prove they had access to ancient coins before certain dates in case future restrictions on coin collecting exempt coins on the collector market before the restrictions are put into place. I unfortunately didn't realize that DigiStamp's certificates are only good for two years when I wrote that piece. I expect a longer certification could be achieved through technical means such as using keys with more bits.
Clicking on the .cer link above runs, at least on my Windows XP machine, the program CERFILE which gives details of the certificate but not the date it was notarized. To see the date the free software from e-Timestamp.com can be used.