I do not sit around and say to myself, “Wow, I sure would like an online resource featuring engravings of 17th century Scotland,” but this is a nice site. John Slezer published his drawings in a book called “Theatrum Scotiae”, which has been turned into a Web site called “Slezer’s Scotland”. This Web site is available at http://www.nls.uk/slezer/ .
You can search by keyword, browse a subject list, or pick sites from a map of Scotland. If you just want to explore, though, may I recommend the highlights list? It’ll provide you a list of images and commentary.
Each engraving’s page has details about the location and the context of the times. You can zoom in and pan around large versions of each engraved image as well — and I mean seriously zoom. You can use a MrSid plugin if your browser has one, but you don’t have to.