Is there any way to know if the window of a window seat is lined up correctly with the seat so I can easily take pictures without unbuckling?

Great question! Airplanes are designed with a set standard of space between the windows. However, not all airlines configure the seating to the same standard. Every time an airline adds or removes a row of seats it changes the spacing for everyone. Usually the window is close enough to allow a claustrophobic passenger a measure of comfort or the ardent photographer with a conveniently-placed view. Occasionally though you may find that the spacing is so far off that there is no visible window at all. There is no sure-fire way to identify these off-kilter situations, though a site such as seatguru.com may sometimes note if there is no window at all.