I'm Making a Collection of Structural and Building Reference Sites, and Thought I could share what I have, and you guys could add some sites that I have missed.
SINE Lots Lots of Images, Separated very nicely by the type of structure, using a map to locate the area, name of the structure, dates, and a few others.
Ruins ImagesIt Has a Few Old Ruins and Stuff.
Earth Quake Destruction Images This has lots of pictures of buildings and stuff after earthquakes.
A Few Pages of Random Images.Has 6 pages of Images.
Newer Buildings and Houses This just has some cool looking buildings and houses.
fotosearch - Architectural You can only view the thumbnails, but theres still some very good images on it.
Custruction Pictures This has pictures of houses, and buildings being constructed and the finished building. The pictures are a little small, but can still be useful.
Lots of Pictures There seems to be a lot of pictures, but they are quite small.
Islamic Architecture This website is all about Islamic stuff, including Architecture. It has blueprints, and pretty big pictures.
Lots of Big Pictures It includes a lot of large pictures.
List of Architects and their websites. Has Quite a few architects listed, some sites don't work.
Muslim Architecture Lots of Good pictures.
Old Architecture Pictures Contains gothic, Roman, prehistoric, 15th, 16th, 17th, 18th, 19th, and 20th century architecture.
Lots more Old Architecture Another Great Site.
Some More Good Gothic Architecture Images Contains a few High Res Images.
Asian Architecture This Site has a lot of Good Asian Architecture images.
Chinese Architecture Good site about Chinese Architecture.
Chinese Architecture 2 Some More Chinese Architecture. Lists the different types too.
Greenland Images A Few Greenland Images.