Method replacesthe tag value if the tag is present in the metadata tree, or null otherwise.

This method accesses the DateTimeOriginal tag. The tag specifies the date and time when the original image data was generated. For a DSC, the date and time the picture was taken are recorded. The format is "YYYY:MM:DD HH:MM:SS" with time shown in 24-hour format, and the date and time separated by one blank character [20.H]. When the date and time are unknown, all the character spaces except colons (":") may be filled with blank characters, or else the Interoperability field may be filled with blank characters.