When were the last pictures taken for Google Maps?

google Maps doesn't display the imagery dates, but google Earth does. That's google Earth the desktop application not the 'Earth' mode found in google Maps.

google reports that the imagery in google Maps and google Earth is on average one to three years old.

Since both use the same imagery database you only need to visit the same area in google Earth and enable the 'Status Bar' in View menu to show the approximate imagery date for a given area in the lower-left corner of the screen.