Super they are. These are aerial photos and you can get them FREE at http://www.britainfromabove.org.uk/
There are several for Stirling, many for the surrounding area and they are easily searchable.
Some of these images will also be on the RCAHMS website but these ones are full size. The site is set to grow and is well worth a browse - a thought which clearly occured to lots of other people as, at first, the site was too busy to let me even