It would depend on what you wanted to find out, but see the link below for a good starting point.
There is no mintmark on the 1921 British Penny, they were all minted at the Royal Mint London.
See the link below.
Pictures of a specific coin are difficult to come by. Usually you should be able to find one on eBay, but the picture is withdrawn after the coin is sold. A 1928 British Penny would be almost identical to the 1936 Penny shown. See the link below.
With the possible exception of traders tokens (with the traders business name on them), there were no "New Zealand" Pennies minted prior to 1940. Any Pennies circulating in New Zealand prior to 1940 would have been mostly British Pennies and some Australian Pennies.
All British Pennies from 1895 to 1901 are near identical. Pictures of a specific coin are difficult to come by. Frequently you should be able to find one on eBay, but the picture is withdrawn after the coin is sold. See the link below for an image of an 1897 British Penny.
Pictures of a specific coin are difficult to come by. Usually you should be able to find one on eBay, but the picture is withdrawn after the coin is sold. All British Pennies from 1911 to 1922 are identical except for the year. See the link below for a 1916 British Penny.
You can tell if a penny is made out of zinc or copper by the date on the penny. If the date is before 1982 then the penny is 95% copper. Pennies dated 1983 or later are 97.5% zinc with a thin copper coating.
I can't find any listings for a British penny with that date. Could you post a new question with additional information, including any wording on the coin and a description of the image on the side that doesn't have the King's picture? NEW : One cent, it does not matter what year it is. A penny is still a penny.
King Edward VII was king in 1908, there are no King George 1908 Pennies.
1936 was the last year British coins were minted with the likeness of George V. The 1936 Penny is far from rare and you should have no trouble finding one.
Pictures of a specific coin are difficult to come by. Usually you should be able to find one on eBay, but the picture is withdrawn after the coin is sold. A 1921 British Penny would be near identical to all British Pennies minted from 1911 to 1922. See the link below for an almost identical 1920 Penny.
in the Library