The birthday announcement
The Royal Family's weekly account for April 16–22, 2022 records Queen Elizabeth II turning 96 on Thursday, April 21. A photograph released for the occasion showed her with two fell ponies; the account says it had been taken at Windsor the preceding month. The image's release date and the date it was photographed therefore were not identical.
Source [1]A separate royal observance
At Royal Maundy on April 14, 2022, the Prince of Wales represented the Queen. The official account describes 96 men and 96 women receiving Maundy money, reflecting her age that year. That ceremony preceded the birthday and had its own purpose and participants.
Keeping these dates separate helps identify what an anniversary photograph or ceremonial report actually shows. This page concerns the Queen's 2022 birthday, not a new celebration or an announcement about a present officeholder. The related UAE succession account also uses official dated records to distinguish the history of a head of state from later leadership developments.
Source [2]